root/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
// SPDX-License-Identifier: MIT
/*
 * Copyright 2012-15 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: AMD
 *
 */

#include <linux/vmalloc.h>
#include <drm/display/drm_dp_helper.h>
#include <drm/display/drm_dp_mst_helper.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_fixed.h>
#include <drm/drm_edid.h>
#include "dm_services.h"
#include "amdgpu.h"
#include "amdgpu_dm.h"
#include "amdgpu_dm_mst_types.h"
#include "amdgpu_dm_hdcp.h"

#include "dc.h"
#include "dm_helpers.h"

#include "ddc_service_types.h"
#include "dpcd_defs.h"

#include "dmub_cmd.h"
#if defined(CONFIG_DEBUG_FS)
#include "amdgpu_dm_debugfs.h"
#endif

#include "dc/resource/dcn20/dcn20_resource.h"

#define PEAK_FACTOR_X1000 1006

/*
 * This function handles both native AUX and I2C-Over-AUX transactions.
 */
static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
                                  struct drm_dp_aux_msg *msg)
{
        ssize_t result = 0;
        struct aux_payload payload;
        enum aux_return_code_type operation_result;
        struct amdgpu_device *adev;
        struct ddc_service *ddc;
        uint8_t copy[16];

        if (WARN_ON(msg->size > 16))
                return -E2BIG;

        payload.address = msg->address;
        payload.data = msg->buffer;
        payload.length = msg->size;
        payload.reply = &msg->reply;
        payload.i2c_over_aux = (msg->request & DP_AUX_NATIVE_WRITE) == 0;
        payload.write = (msg->request & DP_AUX_I2C_READ) == 0;
        payload.mot = (msg->request & DP_AUX_I2C_MOT) != 0;
        payload.write_status_update =
                        (msg->request & DP_AUX_I2C_WRITE_STATUS_UPDATE) != 0;
        payload.defer_delay = 0;

        if (payload.write) {
                memcpy(copy, msg->buffer, msg->size);
                payload.data = copy;
        }

        result = dc_link_aux_transfer_raw(TO_DM_AUX(aux)->ddc_service, &payload,
                                      &operation_result);

        /*
         * w/a on certain intel platform where hpd is unexpected to pull low during
         * 1st sideband message transaction by return AUX_RET_ERROR_HPD_DISCON
         * aux transaction is succuess in such case, therefore bypass the error
         */
        ddc = TO_DM_AUX(aux)->ddc_service;
        adev = ddc->ctx->driver_context;
        if (adev->dm.aux_hpd_discon_quirk) {
                if (msg->address == DP_SIDEBAND_MSG_DOWN_REQ_BASE &&
                        operation_result == AUX_RET_ERROR_HPD_DISCON) {
                        result = msg->size;
                        operation_result = AUX_RET_SUCCESS;
                }
        }

        /*
         * result equals to 0 includes the cases of AUX_DEFER/I2C_DEFER
         */
        if (payload.write && result >= 0) {
                if (result) {
                        /*one byte indicating partially written bytes*/
                        drm_dbg_dp(adev_to_drm(adev), "AUX partially written\n");
                        result = payload.data[0];
                } else if (!payload.reply[0])
                        /*I2C_ACK|AUX_ACK*/
                        result = msg->size;
        }

        if (result < 0) {
                switch (operation_result) {
                case AUX_RET_SUCCESS:
                        break;
                case AUX_RET_ERROR_HPD_DISCON:
                case AUX_RET_ERROR_UNKNOWN:
                case AUX_RET_ERROR_INVALID_OPERATION:
                case AUX_RET_ERROR_PROTOCOL_ERROR:
                        result = -EIO;
                        break;
                case AUX_RET_ERROR_INVALID_REPLY:
                case AUX_RET_ERROR_ENGINE_ACQUIRE:
                        result = -EBUSY;
                        break;
                case AUX_RET_ERROR_TIMEOUT:
                        result = -ETIMEDOUT;
                        break;
                }

                drm_dbg_dp(adev_to_drm(adev), "DP AUX transfer fail:%d\n", operation_result);
        }

        if (payload.reply[0])
                drm_dbg_dp(adev_to_drm(adev), "AUX reply command not ACK: 0x%02x.",
                        payload.reply[0]);

        return result;
}

static void
dm_dp_mst_connector_destroy(struct drm_connector *connector)
{
        struct amdgpu_dm_connector *aconnector =
                to_amdgpu_dm_connector(connector);

        if (aconnector->dc_sink) {
                dc_link_remove_remote_sink(aconnector->dc_link,
                                           aconnector->dc_sink);
                dc_sink_release(aconnector->dc_sink);
        }

        drm_edid_free(aconnector->drm_edid);

        drm_connector_cleanup(connector);
        drm_dp_mst_put_port_malloc(aconnector->mst_output_port);
        kfree(aconnector);
}

static int
amdgpu_dm_mst_connector_late_register(struct drm_connector *connector)
{
        struct amdgpu_dm_connector *amdgpu_dm_connector =
                to_amdgpu_dm_connector(connector);
        int r;

        r = drm_dp_mst_connector_late_register(connector,
                                               amdgpu_dm_connector->mst_output_port);
        if (r < 0)
                return r;

#if defined(CONFIG_DEBUG_FS)
        connector_debugfs_init(amdgpu_dm_connector);
#endif

        return 0;
}


static inline void
amdgpu_dm_mst_reset_mst_connector_setting(struct amdgpu_dm_connector *aconnector)
{
        aconnector->drm_edid = NULL;
        aconnector->dsc_aux = NULL;
        aconnector->mst_output_port->passthrough_aux = NULL;
        aconnector->mst_local_bw = 0;
        aconnector->vc_full_pbn = 0;
}

static void
amdgpu_dm_mst_connector_early_unregister(struct drm_connector *connector)
{
        struct amdgpu_dm_connector *aconnector =
                to_amdgpu_dm_connector(connector);
        struct drm_dp_mst_port *port = aconnector->mst_output_port;
        struct amdgpu_dm_connector *root = aconnector->mst_root;
        struct dc_link *dc_link = aconnector->dc_link;
        struct dc_sink *dc_sink = aconnector->dc_sink;

        drm_dp_mst_connector_early_unregister(connector, port);

        /*
         * Release dc_sink for connector which its attached port is
         * no longer in the mst topology
         */
        drm_modeset_lock(&root->mst_mgr.base.lock, NULL);
        if (dc_sink) {
                if (dc_link->sink_count)
                        dc_link_remove_remote_sink(dc_link, dc_sink);

                drm_dbg_dp(connector->dev,
                           "DM_MST: remove remote sink 0x%p, %d remaining\n",
                           dc_sink, dc_link->sink_count);

                dc_sink_release(dc_sink);
                aconnector->dc_sink = NULL;
                amdgpu_dm_mst_reset_mst_connector_setting(aconnector);
        }

        aconnector->mst_status = MST_STATUS_DEFAULT;
        drm_modeset_unlock(&root->mst_mgr.base.lock);
}

static const struct drm_connector_funcs dm_dp_mst_connector_funcs = {
        .fill_modes = drm_helper_probe_single_connector_modes,
        .destroy = dm_dp_mst_connector_destroy,
        .reset = amdgpu_dm_connector_funcs_reset,
        .atomic_duplicate_state = amdgpu_dm_connector_atomic_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
        .atomic_set_property = amdgpu_dm_connector_atomic_set_property,
        .atomic_get_property = amdgpu_dm_connector_atomic_get_property,
        .late_register = amdgpu_dm_mst_connector_late_register,
        .early_unregister = amdgpu_dm_mst_connector_early_unregister,
};

bool needs_dsc_aux_workaround(struct dc_link *link)
{
        if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 &&
            (link->dpcd_caps.dpcd_rev.raw == DPCD_REV_14 || link->dpcd_caps.dpcd_rev.raw == DPCD_REV_12) &&
            link->dpcd_caps.sink_count.bits.SINK_COUNT >= 2)
                return true;

        return false;
}

#if defined(CONFIG_DRM_AMD_DC_FP)
static bool is_synaptics_cascaded_panamera(struct dc_link *link, struct drm_dp_mst_port *port)
{
        u8 branch_vendor_data[4] = { 0 }; // Vendor data 0x50C ~ 0x50F

        if (drm_dp_dpcd_read(port->mgr->aux, DP_BRANCH_VENDOR_SPECIFIC_START, &branch_vendor_data, 4) == 4) {
                if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 &&
                                IS_SYNAPTICS_CASCADED_PANAMERA(link->dpcd_caps.branch_dev_name, branch_vendor_data)) {
                        DRM_INFO("Synaptics Cascaded MST hub\n");
                        return true;
                }
        }

        return false;
}

static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnector)
{
        struct dc_sink *dc_sink = aconnector->dc_sink;
        struct drm_dp_mst_port *port = aconnector->mst_output_port;
        u8 dsc_caps[16] = { 0 };
        u8 dsc_branch_dec_caps_raw[3] = { 0 };  // DSC branch decoder caps 0xA0 ~ 0xA2
        u8 *dsc_branch_dec_caps = NULL;

        aconnector->dsc_aux = drm_dp_mst_dsc_aux_for_port(port);

        /*
         * drm_dp_mst_dsc_aux_for_port() will return NULL for certain configs
         * because it only check the dsc/fec caps of the "port variable" and not the dock
         *
         * This case will return NULL: DSC capabe MST dock connected to a non fec/dsc capable display
         *
         * Workaround: explicitly check the use case above and use the mst dock's aux as dsc_aux
         *
         */
        if (!aconnector->dsc_aux && !port->parent->port_parent &&
            needs_dsc_aux_workaround(aconnector->dc_link))
                aconnector->dsc_aux = &aconnector->mst_root->dm_dp_aux.aux;

        /* synaptics cascaded MST hub case */
        if (is_synaptics_cascaded_panamera(aconnector->dc_link, port))
                aconnector->dsc_aux = port->mgr->aux;

        if (!aconnector->dsc_aux)
                return false;

        if (drm_dp_dpcd_read(aconnector->dsc_aux, DP_DSC_SUPPORT, dsc_caps, 16) < 0)
                return false;

        if (drm_dp_dpcd_read(aconnector->dsc_aux,
                        DP_DSC_BRANCH_OVERALL_THROUGHPUT_0, dsc_branch_dec_caps_raw, 3) == 3)
                dsc_branch_dec_caps = dsc_branch_dec_caps_raw;

        if (!dc_dsc_parse_dsc_dpcd(aconnector->dc_link->ctx->dc,
                                  dsc_caps, dsc_branch_dec_caps,
                                  &dc_sink->dsc_caps.dsc_dec_caps))
                return false;

        return true;
}
#endif

static bool retrieve_downstream_port_device(struct amdgpu_dm_connector *aconnector)
{
        union dp_downstream_port_present ds_port_present;

        if (!aconnector->dsc_aux)
                return false;

        if (drm_dp_dpcd_read(aconnector->dsc_aux, DP_DOWNSTREAMPORT_PRESENT, &ds_port_present, 1) < 0) {
                DRM_INFO("Failed to read downstream_port_present 0x05 from DFP of branch device\n");
                return false;
        }

        aconnector->mst_downstream_port_present = ds_port_present;
        DRM_INFO("Downstream port present %d, type %d\n",
                        ds_port_present.fields.PORT_PRESENT, ds_port_present.fields.PORT_TYPE);

        return true;
}

static bool retrieve_branch_specific_data(struct amdgpu_dm_connector *aconnector)
{
        struct drm_connector *connector = &aconnector->base;
        struct drm_dp_mst_port *port = aconnector->mst_output_port;
        struct drm_dp_mst_port *port_parent;
        struct drm_dp_aux *immediate_upstream_aux;
        struct drm_dp_desc branch_desc;

        if (!port->parent)
                return false;

        port_parent = port->parent->port_parent;

        immediate_upstream_aux = port_parent ? &port_parent->aux : port->mgr->aux;

        if (drm_dp_read_desc(immediate_upstream_aux, &branch_desc, true))
                return false;

        aconnector->branch_ieee_oui = (branch_desc.ident.oui[0] << 16) +
                                      (branch_desc.ident.oui[1] << 8) +
                                      (branch_desc.ident.oui[2]);

        drm_dbg_dp(port->aux.drm_dev, "MST branch oui 0x%x detected at %s\n",
                   aconnector->branch_ieee_oui, connector->name);

        return true;
}

static int dm_dp_mst_get_modes(struct drm_connector *connector)
{
        struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
        int ret = 0;

        if (!aconnector)
                return drm_add_edid_modes(connector, NULL);

        if (!aconnector->drm_edid) {
                const struct drm_edid *drm_edid;

                drm_edid = drm_dp_mst_edid_read(connector,
                                                &aconnector->mst_root->mst_mgr,
                                                aconnector->mst_output_port);

                if (!drm_edid) {
                        amdgpu_dm_set_mst_status(&aconnector->mst_status,
                        MST_REMOTE_EDID, false);

                        drm_edid_connector_update(
                                &aconnector->base,
                                NULL);

                        DRM_DEBUG_KMS("Can't get EDID of %s. Add default remote sink.", connector->name);
                        if (!aconnector->dc_sink) {
                                struct dc_sink *dc_sink;
                                struct dc_sink_init_data init_params = {
                                        .link = aconnector->dc_link,
                                        .sink_signal = SIGNAL_TYPE_DISPLAY_PORT_MST };

                                dc_sink = dc_link_add_remote_sink(
                                        aconnector->dc_link,
                                        NULL,
                                        0,
                                        &init_params);

                                if (!dc_sink) {
                                        DRM_ERROR("Unable to add a remote sink\n");
                                        return 0;
                                }

                                drm_dbg_dp(connector->dev,
                                           "DM_MST: add remote sink 0x%p, %d remaining\n",
                                           dc_sink,
                                           aconnector->dc_link->sink_count);

                                dc_sink->priv = aconnector;
                                aconnector->dc_sink = dc_sink;
                        }

                        return ret;
                }

                aconnector->drm_edid = drm_edid;
                amdgpu_dm_set_mst_status(&aconnector->mst_status,
                        MST_REMOTE_EDID, true);
        }

        if (aconnector->dc_sink && aconnector->dc_sink->sink_signal == SIGNAL_TYPE_VIRTUAL) {
                dc_sink_release(aconnector->dc_sink);
                aconnector->dc_sink = NULL;
        }

        if (!aconnector->dc_sink) {
                struct dc_sink *dc_sink;
                struct dc_sink_init_data init_params = {
                                .link = aconnector->dc_link,
                                .sink_signal = SIGNAL_TYPE_DISPLAY_PORT_MST };
                const struct edid *edid;

                edid = drm_edid_raw(aconnector->drm_edid); // FIXME: Get rid of drm_edid_raw()
                dc_sink = dc_link_add_remote_sink(
                        aconnector->dc_link,
                        (uint8_t *)edid,
                        (edid->extensions + 1) * EDID_LENGTH,
                        &init_params);

                if (!dc_sink) {
                        DRM_ERROR("Unable to add a remote sink\n");
                        return 0;
                }

                drm_dbg_dp(connector->dev,
                           "DM_MST: add remote sink 0x%p, %d remaining\n",
                           dc_sink, aconnector->dc_link->sink_count);

                dc_sink->priv = aconnector;
                /* dc_link_add_remote_sink returns a new reference */
                aconnector->dc_sink = dc_sink;

                /* when display is unplugged from mst hub, connctor will be
                 * destroyed within dm_dp_mst_connector_destroy. connector
                 * hdcp perperties, like type, undesired, desired, enabled,
                 * will be lost. So, save hdcp properties into hdcp_work within
                 * amdgpu_dm_atomic_commit_tail. if the same display is
                 * plugged back with same display index, its hdcp properties
                 * will be retrieved from hdcp_work within dm_dp_mst_get_modes
                 */
                if (aconnector->dc_sink && connector->state) {
                        struct drm_device *dev = connector->dev;
                        struct amdgpu_device *adev = drm_to_adev(dev);

                        if (adev->dm.hdcp_workqueue) {
                                struct hdcp_workqueue *hdcp_work = adev->dm.hdcp_workqueue;
                                struct hdcp_workqueue *hdcp_w =
                                        &hdcp_work[aconnector->dc_link->link_index];

                                connector->state->hdcp_content_type =
                                hdcp_w->hdcp_content_type[connector->index];
                                connector->state->content_protection =
                                hdcp_w->content_protection[connector->index];
                        }
                }

                if (aconnector->dc_sink) {
                        amdgpu_dm_update_freesync_caps(
                                        connector, aconnector->drm_edid);

#if defined(CONFIG_DRM_AMD_DC_FP)
                        if (!validate_dsc_caps_on_connector(aconnector))
                                memset(&aconnector->dc_sink->dsc_caps,
                                       0, sizeof(aconnector->dc_sink->dsc_caps));
#endif

                        if (!retrieve_downstream_port_device(aconnector))
                                memset(&aconnector->mst_downstream_port_present,
                                        0, sizeof(aconnector->mst_downstream_port_present));
                }
        }

        drm_edid_connector_update(&aconnector->base, aconnector->drm_edid);

        ret = drm_edid_connector_add_modes(connector);

        return ret;
}

static struct drm_encoder *
dm_mst_atomic_best_encoder(struct drm_connector *connector,
                           struct drm_atomic_state *state)
{
        struct drm_connector_state *connector_state = drm_atomic_get_new_connector_state(state,
                                                                                         connector);
        struct amdgpu_device *adev = drm_to_adev(connector->dev);
        struct amdgpu_crtc *acrtc = to_amdgpu_crtc(connector_state->crtc);

        return &adev->dm.mst_encoders[acrtc->crtc_id].base;
}

static int
dm_dp_mst_detect(struct drm_connector *connector,
                 struct drm_modeset_acquire_ctx *ctx, bool force)
{
        struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
        struct amdgpu_dm_connector *master = aconnector->mst_root;
        struct drm_dp_mst_port *port = aconnector->mst_output_port;
        int connection_status;

        if (drm_connector_is_unregistered(connector))
                return connector_status_disconnected;

        connection_status = drm_dp_mst_detect_port(connector, ctx, &master->mst_mgr,
                                                        aconnector->mst_output_port);

        if (port->pdt != DP_PEER_DEVICE_NONE && !port->dpcd_rev) {
                uint8_t dpcd_rev;
                int ret;

                ret = drm_dp_dpcd_readb(&port->aux, DP_DP13_DPCD_REV, &dpcd_rev);

                if (ret == 1) {
                        port->dpcd_rev = dpcd_rev;

                        /* Could be DP1.2 DP Rx case*/
                        if (!dpcd_rev) {
                                ret = drm_dp_dpcd_readb(&port->aux, DP_DPCD_REV, &dpcd_rev);

                                if (ret == 1)
                                        port->dpcd_rev = dpcd_rev;
                        }

                        if (!dpcd_rev)
                                DRM_DEBUG_KMS("Can't decide DPCD revision number!");
                }

                /*
                 * Could be legacy sink, logical port etc on DP1.2.
                 * Will get Nack under these cases when issue remote
                 * DPCD read.
                 */
                if (ret != 1)
                        DRM_DEBUG_KMS("Can't access DPCD");
        } else if (port->pdt == DP_PEER_DEVICE_NONE) {
                port->dpcd_rev = 0;
        }

        /*
         * Release dc_sink for connector which unplug event is notified by CSN msg
         */
        if (connection_status == connector_status_disconnected && aconnector->dc_sink) {
                if (aconnector->dc_link->sink_count)
                        dc_link_remove_remote_sink(aconnector->dc_link, aconnector->dc_sink);

                drm_dbg_dp(connector->dev,
                           "DM_MST: remove remote sink 0x%p, %d remaining\n",
                           aconnector->dc_link,
                           aconnector->dc_link->sink_count);

                dc_sink_release(aconnector->dc_sink);
                aconnector->dc_sink = NULL;
                amdgpu_dm_mst_reset_mst_connector_setting(aconnector);

                amdgpu_dm_set_mst_status(&aconnector->mst_status,
                        MST_REMOTE_EDID | MST_ALLOCATE_NEW_PAYLOAD | MST_CLEAR_ALLOCATED_PAYLOAD,
                        false);
        }

        return connection_status;
}

static int dm_dp_mst_atomic_check(struct drm_connector *connector,
                                  struct drm_atomic_state *state)
{
        struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
        struct drm_dp_mst_topology_mgr *mst_mgr = &aconnector->mst_root->mst_mgr;
        struct drm_dp_mst_port *mst_port = aconnector->mst_output_port;

        return drm_dp_atomic_release_time_slots(state, mst_mgr, mst_port);
}

static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs = {
        .get_modes = dm_dp_mst_get_modes,
        .mode_valid = amdgpu_dm_connector_mode_valid,
        .atomic_best_encoder = dm_mst_atomic_best_encoder,
        .detect_ctx = dm_dp_mst_detect,
        .atomic_check = dm_dp_mst_atomic_check,
};

static void amdgpu_dm_encoder_destroy(struct drm_encoder *encoder)
{
        drm_encoder_cleanup(encoder);
}

static const struct drm_encoder_funcs amdgpu_dm_encoder_funcs = {
        .destroy = amdgpu_dm_encoder_destroy,
};

void
dm_dp_create_fake_mst_encoders(struct amdgpu_device *adev)
{
        struct drm_device *dev = adev_to_drm(adev);
        int i;

        for (i = 0; i < adev->dm.display_indexes_num; i++) {
                struct amdgpu_encoder *amdgpu_encoder = &adev->dm.mst_encoders[i];
                struct drm_encoder *encoder = &amdgpu_encoder->base;

                encoder->possible_crtcs = amdgpu_dm_get_encoder_crtc_mask(adev);

                drm_encoder_init(
                        dev,
                        &amdgpu_encoder->base,
                        &amdgpu_dm_encoder_funcs,
                        DRM_MODE_ENCODER_DPMST,
                        NULL);

                drm_encoder_helper_add(encoder, &amdgpu_dm_encoder_helper_funcs);
        }
}

static struct drm_connector *
dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
                        struct drm_dp_mst_port *port,
                        const char *pathprop)
{
        struct amdgpu_dm_connector *master = container_of(mgr, struct amdgpu_dm_connector, mst_mgr);
        struct drm_device *dev = master->base.dev;
        struct amdgpu_device *adev = drm_to_adev(dev);
        struct amdgpu_dm_connector *aconnector;
        struct drm_connector *connector;
        int i;

        aconnector = kzalloc(sizeof(*aconnector), GFP_KERNEL);
        if (!aconnector)
                return NULL;

        DRM_DEBUG_DRIVER("%s: Create aconnector 0x%p for port 0x%p\n", __func__, aconnector, port);

        connector = &aconnector->base;
        aconnector->mst_output_port = port;
        aconnector->mst_root = master;
        amdgpu_dm_set_mst_status(&aconnector->mst_status,
                        MST_PROBE, true);

        if (drm_connector_dynamic_init(
                dev,
                connector,
                &dm_dp_mst_connector_funcs,
                DRM_MODE_CONNECTOR_DisplayPort,
                NULL)) {
                kfree(aconnector);
                return NULL;
        }
        drm_connector_helper_add(connector, &dm_dp_mst_connector_helper_funcs);

        amdgpu_dm_connector_init_helper(
                &adev->dm,
                aconnector,
                DRM_MODE_CONNECTOR_DisplayPort,
                master->dc_link,
                master->connector_id);

        for (i = 0; i < adev->dm.display_indexes_num; i++) {
                drm_connector_attach_encoder(&aconnector->base,
                                             &adev->dm.mst_encoders[i].base);
        }

        connector->max_bpc_property = master->base.max_bpc_property;
        if (connector->max_bpc_property)
                drm_connector_attach_max_bpc_property(connector, 8, 16);

        connector->vrr_capable_property = master->base.vrr_capable_property;
        if (connector->vrr_capable_property)
                drm_connector_attach_vrr_capable_property(connector);

        drm_object_attach_property(
                &connector->base,
                dev->mode_config.path_property,
                0);
        drm_object_attach_property(
                &connector->base,
                dev->mode_config.tile_property,
                0);
        connector->colorspace_property = master->base.colorspace_property;
        if (connector->colorspace_property)
                drm_connector_attach_colorspace_property(connector);

        drm_connector_set_path_property(connector, pathprop);

        if (!retrieve_branch_specific_data(aconnector))
                aconnector->branch_ieee_oui = 0;

        /*
         * Initialize connector state before adding the connectror to drm and
         * framebuffer lists
         */
        amdgpu_dm_connector_funcs_reset(connector);

        drm_dp_mst_get_port_malloc(port);

        return connector;
}

void dm_handle_mst_sideband_msg_ready_event(
        struct drm_dp_mst_topology_mgr *mgr,
        enum mst_msg_ready_type msg_rdy_type)
{
        uint8_t esi[DP_PSR_ERROR_STATUS - DP_SINK_COUNT_ESI] = { 0 };
        uint8_t dret;
        bool new_irq_handled = false;
        int dpcd_addr;
        uint8_t dpcd_bytes_to_read;
        const uint8_t max_process_count = 30;
        uint8_t process_count = 0;
        u8 retry;
        struct amdgpu_dm_connector *aconnector =
                        container_of(mgr, struct amdgpu_dm_connector, mst_mgr);


        const struct dc_link_status *link_status = dc_link_get_status(aconnector->dc_link);

        if (link_status->dpcd_caps->dpcd_rev.raw < 0x12) {
                dpcd_bytes_to_read = DP_LANE0_1_STATUS - DP_SINK_COUNT;
                /* DPCD 0x200 - 0x201 for downstream IRQ */
                dpcd_addr = DP_SINK_COUNT;
        } else {
                dpcd_bytes_to_read = DP_PSR_ERROR_STATUS - DP_SINK_COUNT_ESI;
                /* DPCD 0x2002 - 0x2005 for downstream IRQ */
                dpcd_addr = DP_SINK_COUNT_ESI;
        }

        mutex_lock(&aconnector->handle_mst_msg_ready);

        while (process_count < max_process_count) {
                u8 ack[DP_PSR_ERROR_STATUS - DP_SINK_COUNT_ESI] = {};

                process_count++;

                dret = drm_dp_dpcd_read(
                        &aconnector->dm_dp_aux.aux,
                        dpcd_addr,
                        esi,
                        dpcd_bytes_to_read);

                if (dret != dpcd_bytes_to_read) {
                        DRM_DEBUG_KMS("DPCD read and acked number is not as expected!");
                        break;
                }

                DRM_DEBUG_DRIVER("ESI %02x %02x %02x\n", esi[0], esi[1], esi[2]);

                switch (msg_rdy_type) {
                case DOWN_REP_MSG_RDY_EVENT:
                        /* Only handle DOWN_REP_MSG_RDY case*/
                        esi[1] &= DP_DOWN_REP_MSG_RDY;
                        break;
                case UP_REQ_MSG_RDY_EVENT:
                        /* Only handle UP_REQ_MSG_RDY case*/
                        esi[1] &= DP_UP_REQ_MSG_RDY;
                        break;
                default:
                        /* Handle both cases*/
                        esi[1] &= (DP_DOWN_REP_MSG_RDY | DP_UP_REQ_MSG_RDY);
                        break;
                }

                if (!esi[1])
                        break;

                /* handle MST irq */
                if (aconnector->mst_mgr.mst_state)
                        drm_dp_mst_hpd_irq_handle_event(&aconnector->mst_mgr,
                                                 esi,
                                                 ack,
                                                 &new_irq_handled);

                if (new_irq_handled) {
                        /* ACK at DPCD to notify down stream */
                        for (retry = 0; retry < 3; retry++) {
                                ssize_t wret;

                                wret = drm_dp_dpcd_writeb(&aconnector->dm_dp_aux.aux,
                                                          dpcd_addr + 1,
                                                          ack[1]);
                                if (wret == 1)
                                        break;
                        }

                        if (retry == 3) {
                                DRM_ERROR("Failed to ack MST event.\n");
                                break;
                        }

                        drm_dp_mst_hpd_irq_send_new_request(&aconnector->mst_mgr);

                        new_irq_handled = false;
                } else {
                        break;
                }
        }

        mutex_unlock(&aconnector->handle_mst_msg_ready);

        if (process_count == max_process_count)
                DRM_DEBUG_DRIVER("Loop exceeded max iterations\n");
}

static void dm_handle_mst_down_rep_msg_ready(struct drm_dp_mst_topology_mgr *mgr)
{
        dm_handle_mst_sideband_msg_ready_event(mgr, DOWN_REP_MSG_RDY_EVENT);
}

static const struct drm_dp_mst_topology_cbs dm_mst_cbs = {
        .add_connector = dm_dp_add_mst_connector,
        .poll_hpd_irq = dm_handle_mst_down_rep_msg_ready,
};

void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
                                       struct amdgpu_dm_connector *aconnector,
                                       int link_index)
{
        struct dc_link_settings max_link_enc_cap = {0};

        aconnector->dm_dp_aux.aux.name =
                kasprintf(GFP_KERNEL, "AMDGPU DM aux hw bus %d",
                          link_index);
        aconnector->dm_dp_aux.aux.transfer = dm_dp_aux_transfer;
        aconnector->dm_dp_aux.aux.drm_dev = dm->ddev;
        aconnector->dm_dp_aux.ddc_service = aconnector->dc_link->ddc;

        drm_dp_aux_init(&aconnector->dm_dp_aux.aux);
        drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
                                      &aconnector->base);
        drm_dp_dpcd_set_probe(&aconnector->dm_dp_aux.aux, false);

        if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_eDP)
                return;

        dc_link_dp_get_max_link_enc_cap(aconnector->dc_link, &max_link_enc_cap);
        aconnector->mst_mgr.cbs = &dm_mst_cbs;
        drm_dp_mst_topology_mgr_init(&aconnector->mst_mgr, adev_to_drm(dm->adev),
                                     &aconnector->dm_dp_aux.aux, 16, 4, aconnector->connector_id);

        drm_connector_attach_dp_subconnector_property(&aconnector->base);
}

uint32_t dm_mst_get_pbn_divider(struct dc_link *link)
{
        uint32_t pbn_div_x100;
        uint64_t dividend, divisor;

        if (!link)
                return 0;

        dividend = (uint64_t)dc_link_bandwidth_kbps(link, dc_link_get_link_cap(link)) * 100;
        divisor = 8 * 1000 * 54;

        pbn_div_x100 = div64_u64(dividend, divisor);

        return dfixed_const(pbn_div_x100) / 100;
}

struct dsc_mst_fairness_params {
        struct dc_crtc_timing *timing;
        struct dc_sink *sink;
        struct dc_dsc_bw_range bw_range;
        bool compression_possible;
        struct drm_dp_mst_port *port;
        enum dsc_clock_force_state clock_force_enable;
        uint32_t num_slices_h;
        uint32_t num_slices_v;
        uint32_t bpp_overwrite;
        struct amdgpu_dm_connector *aconnector;
};

#if defined(CONFIG_DRM_AMD_DC_FP)
static uint16_t get_fec_overhead_multiplier(struct dc_link *dc_link)
{
        u8 link_coding_cap;
        uint16_t fec_overhead_multiplier_x1000 = PBN_FEC_OVERHEAD_MULTIPLIER_8B_10B;

        link_coding_cap = dc_link_dp_mst_decide_link_encoding_format(dc_link);
        if (link_coding_cap == DP_128b_132b_ENCODING)
                fec_overhead_multiplier_x1000 = PBN_FEC_OVERHEAD_MULTIPLIER_128B_132B;

        return fec_overhead_multiplier_x1000;
}

static int kbps_to_peak_pbn(int kbps, uint16_t fec_overhead_multiplier_x1000)
{
        u64 peak_kbps = kbps;

        peak_kbps *= 1006;
        peak_kbps *= fec_overhead_multiplier_x1000;
        peak_kbps = div_u64(peak_kbps, 1000 * 1000);
        return (int) DIV64_U64_ROUND_UP(peak_kbps * 64, (54 * 8 * 1000));
}

static void set_dsc_configs_from_fairness_vars(struct dsc_mst_fairness_params *params,
                struct dsc_mst_fairness_vars *vars,
                int count,
                int k)
{
        struct drm_connector *drm_connector;
        int i;
        struct dc_dsc_config_options dsc_options = {0};

        for (i = 0; i < count; i++) {
                drm_connector = &params[i].aconnector->base;

                dc_dsc_get_default_config_option(params[i].sink->ctx->dc, &dsc_options);
                dsc_options.max_target_bpp_limit_override_x16 = drm_connector->display_info.max_dsc_bpp * 16;

                memset(&params[i].timing->dsc_cfg, 0, sizeof(params[i].timing->dsc_cfg));
                if (vars[i + k].dsc_enabled && dc_dsc_compute_config(
                                        params[i].sink->ctx->dc->res_pool->dscs[0],
                                        &params[i].sink->dsc_caps.dsc_dec_caps,
                                        &dsc_options,
                                        0,
                                        params[i].timing,
                                        dc_link_get_highest_encoding_format(params[i].aconnector->dc_link),
                                        &params[i].timing->dsc_cfg)) {
                        params[i].timing->flags.DSC = 1;

                        if (params[i].bpp_overwrite)
                                params[i].timing->dsc_cfg.bits_per_pixel = params[i].bpp_overwrite;
                        else
                                params[i].timing->dsc_cfg.bits_per_pixel = vars[i + k].bpp_x16;

                        if (params[i].num_slices_h)
                                params[i].timing->dsc_cfg.num_slices_h = params[i].num_slices_h;

                        if (params[i].num_slices_v)
                                params[i].timing->dsc_cfg.num_slices_v = params[i].num_slices_v;
                } else {
                        params[i].timing->flags.DSC = 0;
                }
                params[i].timing->dsc_cfg.mst_pbn = vars[i + k].pbn;
        }

        for (i = 0; i < count; i++) {
                if (params[i].sink) {
                        if (params[i].sink->sink_signal != SIGNAL_TYPE_VIRTUAL &&
                                params[i].sink->sink_signal != SIGNAL_TYPE_NONE)
                                DRM_DEBUG_DRIVER("MST_DSC %s i=%d dispname=%s\n", __func__, i,
                                        params[i].sink->edid_caps.display_name);
                }

                DRM_DEBUG_DRIVER("MST_DSC dsc=%d bits_per_pixel=%d pbn=%d\n",
                        params[i].timing->flags.DSC,
                        params[i].timing->dsc_cfg.bits_per_pixel,
                        vars[i + k].pbn);
        }
}

static int bpp_x16_from_pbn(struct dsc_mst_fairness_params param, int pbn)
{
        struct dc_dsc_config dsc_config;
        u64 kbps;

        struct drm_connector *drm_connector = &param.aconnector->base;
        struct dc_dsc_config_options dsc_options = {0};

        dc_dsc_get_default_config_option(param.sink->ctx->dc, &dsc_options);
        dsc_options.max_target_bpp_limit_override_x16 = drm_connector->display_info.max_dsc_bpp * 16;

        kbps = div_u64((u64)pbn * 994 * 8 * 54, 64);
        dc_dsc_compute_config(
                        param.sink->ctx->dc->res_pool->dscs[0],
                        &param.sink->dsc_caps.dsc_dec_caps,
                        &dsc_options,
                        (int) kbps, param.timing,
                        dc_link_get_highest_encoding_format(param.aconnector->dc_link),
                        &dsc_config);

        return dsc_config.bits_per_pixel;
}

static int increase_dsc_bpp(struct drm_atomic_state *state,
                            struct drm_dp_mst_topology_state *mst_state,
                            struct dc_link *dc_link,
                            struct dsc_mst_fairness_params *params,
                            struct dsc_mst_fairness_vars *vars,
                            int count,
                            int k)
{
        int i;
        bool bpp_increased[MAX_PIPES];
        int initial_slack[MAX_PIPES];
        int min_initial_slack;
        int next_index;
        int remaining_to_increase = 0;
        int link_timeslots_used;
        int fair_pbn_alloc;
        int ret = 0;
        uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);

        for (i = 0; i < count; i++) {
                if (vars[i + k].dsc_enabled) {
                        initial_slack[i] =
                        kbps_to_peak_pbn(params[i].bw_range.max_kbps, fec_overhead_multiplier_x1000) - vars[i + k].pbn;
                        bpp_increased[i] = false;
                        remaining_to_increase += 1;
                } else {
                        initial_slack[i] = 0;
                        bpp_increased[i] = true;
                }
        }

        while (remaining_to_increase) {
                next_index = -1;
                min_initial_slack = -1;
                for (i = 0; i < count; i++) {
                        if (!bpp_increased[i]) {
                                if (min_initial_slack == -1 || min_initial_slack > initial_slack[i]) {
                                        min_initial_slack = initial_slack[i];
                                        next_index = i;
                                }
                        }
                }

                if (next_index == -1)
                        break;

                link_timeslots_used = 0;

                for (i = 0; i < count; i++)
                        link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, dfixed_trunc(mst_state->pbn_div));

                fair_pbn_alloc =
                        (63 - link_timeslots_used) / remaining_to_increase * dfixed_trunc(mst_state->pbn_div);

                if (initial_slack[next_index] > fair_pbn_alloc) {
                        vars[next_index].pbn += fair_pbn_alloc;
                        ret = drm_dp_atomic_find_time_slots(state,
                                                            params[next_index].port->mgr,
                                                            params[next_index].port,
                                                            vars[next_index].pbn);
                        if (ret < 0)
                                return ret;

                        ret = drm_dp_mst_atomic_check(state);
                        if (ret == 0) {
                                vars[next_index].bpp_x16 = bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
                        } else {
                                vars[next_index].pbn -= fair_pbn_alloc;
                                ret = drm_dp_atomic_find_time_slots(state,
                                                                    params[next_index].port->mgr,
                                                                    params[next_index].port,
                                                                    vars[next_index].pbn);
                                if (ret < 0)
                                        return ret;
                        }
                } else {
                        vars[next_index].pbn += initial_slack[next_index];
                        ret = drm_dp_atomic_find_time_slots(state,
                                                            params[next_index].port->mgr,
                                                            params[next_index].port,
                                                            vars[next_index].pbn);
                        if (ret < 0)
                                return ret;

                        ret = drm_dp_mst_atomic_check(state);
                        if (ret == 0) {
                                vars[next_index].bpp_x16 = params[next_index].bw_range.max_target_bpp_x16;
                        } else {
                                vars[next_index].pbn -= initial_slack[next_index];
                                ret = drm_dp_atomic_find_time_slots(state,
                                                                    params[next_index].port->mgr,
                                                                    params[next_index].port,
                                                                    vars[next_index].pbn);
                                if (ret < 0)
                                        return ret;
                        }
                }

                bpp_increased[next_index] = true;
                remaining_to_increase--;
        }
        return 0;
}

static int try_disable_dsc(struct drm_atomic_state *state,
                           struct dc_link *dc_link,
                           struct dsc_mst_fairness_params *params,
                           struct dsc_mst_fairness_vars *vars,
                           int count,
                           int k)
{
        int i;
        bool tried[MAX_PIPES];
        int kbps_increase[MAX_PIPES];
        int max_kbps_increase;
        int next_index;
        int remaining_to_try = 0;
        int ret;
        uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);
        int var_pbn;

        for (i = 0; i < count; i++) {
                if (vars[i + k].dsc_enabled
                                && vars[i + k].bpp_x16 == params[i].bw_range.max_target_bpp_x16
                                && params[i].clock_force_enable == DSC_CLK_FORCE_DEFAULT) {
                        kbps_increase[i] = params[i].bw_range.stream_kbps - params[i].bw_range.max_kbps;
                        tried[i] = false;
                        remaining_to_try += 1;
                } else {
                        kbps_increase[i] = 0;
                        tried[i] = true;
                }
        }

        while (remaining_to_try) {
                next_index = -1;
                max_kbps_increase = -1;
                for (i = 0; i < count; i++) {
                        if (!tried[i]) {
                                if (max_kbps_increase == -1 || max_kbps_increase < kbps_increase[i]) {
                                        max_kbps_increase = kbps_increase[i];
                                        next_index = i;
                                }
                        }
                }

                if (next_index == -1)
                        break;

                DRM_DEBUG_DRIVER("MST_DSC index #%d, try no compression\n", next_index);
                var_pbn = vars[next_index].pbn;
                vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps, fec_overhead_multiplier_x1000);
                ret = drm_dp_atomic_find_time_slots(state,
                                                    params[next_index].port->mgr,
                                                    params[next_index].port,
                                                    vars[next_index].pbn);
                if (ret < 0) {
                        DRM_DEBUG_DRIVER("%s:%d MST_DSC index #%d, failed to set pbn to the state, %d\n",
                                                __func__, __LINE__, next_index, ret);
                        vars[next_index].pbn = var_pbn;
                        return ret;
                }

                ret = drm_dp_mst_atomic_check(state);
                if (ret == 0) {
                        DRM_DEBUG_DRIVER("MST_DSC index #%d, greedily disable dsc\n", next_index);
                        vars[next_index].dsc_enabled = false;
                        vars[next_index].bpp_x16 = 0;
                } else {
                        DRM_DEBUG_DRIVER("MST_DSC index #%d, restore optimized pbn value\n", next_index);
                        vars[next_index].pbn = var_pbn;
                        ret = drm_dp_atomic_find_time_slots(state,
                                                            params[next_index].port->mgr,
                                                            params[next_index].port,
                                                            vars[next_index].pbn);
                        if (ret < 0) {
                                DRM_DEBUG_DRIVER("%s:%d MST_DSC index #%d, failed to set pbn to the state, %d\n",
                                                        __func__, __LINE__, next_index, ret);
                                return ret;
                        }
                }

                tried[next_index] = true;
                remaining_to_try--;
        }
        return 0;
}

static void log_dsc_params(int count, struct dsc_mst_fairness_vars *vars, int k)
{
        int i;

        for (i = 0; i < count; i++)
                DRM_DEBUG_DRIVER("MST_DSC DSC params: stream #%d --- dsc_enabled = %d, bpp_x16 = %d, pbn = %d\n",
                                 i, vars[i + k].dsc_enabled, vars[i + k].bpp_x16, vars[i + k].pbn);
}

static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
                                            struct dc_state *dc_state,
                                            struct dc_link *dc_link,
                                            struct dsc_mst_fairness_vars *vars,
                                            struct drm_dp_mst_topology_mgr *mgr,
                                            int *link_vars_start_index)
{
        struct dc_stream_state *stream;
        struct dsc_mst_fairness_params params[MAX_PIPES];
        struct amdgpu_dm_connector *aconnector;
        struct drm_dp_mst_topology_state *mst_state = drm_atomic_get_mst_topology_state(state, mgr);
        int count = 0;
        int i, k, ret;
        bool debugfs_overwrite = false;
        uint16_t fec_overhead_multiplier_x1000 = get_fec_overhead_multiplier(dc_link);
        struct drm_connector_state *new_conn_state;

        memset(params, 0, sizeof(params));

        if (IS_ERR(mst_state))
                return PTR_ERR(mst_state);

        /* Set up params */
        DRM_DEBUG_DRIVER("%s: MST_DSC Try to set up params from %d streams\n", __func__, dc_state->stream_count);
        for (i = 0; i < dc_state->stream_count; i++) {
                struct dc_dsc_policy dsc_policy = {0};

                stream = dc_state->streams[i];

                if (stream->link != dc_link)
                        continue;

                aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
                if (!aconnector)
                        continue;

                if (!aconnector->mst_output_port)
                        continue;

                new_conn_state = drm_atomic_get_new_connector_state(state, &aconnector->base);

                if (!new_conn_state) {
                        DRM_DEBUG_DRIVER("%s:%d MST_DSC Skip the stream 0x%p with invalid new_conn_state\n",
                                        __func__, __LINE__, stream);
                        continue;
                }

                stream->timing.flags.DSC = 0;

                params[count].timing = &stream->timing;
                params[count].sink = stream->sink;
                params[count].aconnector = aconnector;
                params[count].port = aconnector->mst_output_port;
                params[count].clock_force_enable = aconnector->dsc_settings.dsc_force_enable;
                if (params[count].clock_force_enable == DSC_CLK_FORCE_ENABLE)
                        debugfs_overwrite = true;
                params[count].num_slices_h = aconnector->dsc_settings.dsc_num_slices_h;
                params[count].num_slices_v = aconnector->dsc_settings.dsc_num_slices_v;
                params[count].bpp_overwrite = aconnector->dsc_settings.dsc_bits_per_pixel;
                params[count].compression_possible = stream->sink->dsc_caps.dsc_dec_caps.is_dsc_supported;
                dc_dsc_get_policy_for_timing(params[count].timing, 0, &dsc_policy, dc_link_get_highest_encoding_format(stream->link));
                if (!dc_dsc_compute_bandwidth_range(
                                stream->sink->ctx->dc->res_pool->dscs[0],
                                stream->sink->ctx->dc->debug.dsc_min_slice_height_override,
                                dsc_policy.min_target_bpp * 16,
                                dsc_policy.max_target_bpp * 16,
                                &stream->sink->dsc_caps.dsc_dec_caps,
                                &stream->timing,
                                dc_link_get_highest_encoding_format(dc_link),
                                &params[count].bw_range))
                        params[count].bw_range.stream_kbps = dc_bandwidth_in_kbps_from_timing(&stream->timing,
                                        dc_link_get_highest_encoding_format(dc_link));

                DRM_DEBUG_DRIVER("MST_DSC #%d stream 0x%p - max_kbps = %u, min_kbps = %u, uncompressed_kbps = %u\n",
                        count, stream, params[count].bw_range.max_kbps, params[count].bw_range.min_kbps,
                        params[count].bw_range.stream_kbps);
                count++;
        }

        DRM_DEBUG_DRIVER("%s: MST_DSC Params set up for %d streams\n", __func__, count);

        if (count == 0) {
                ASSERT(0);
                return 0;
        }

        /* k is start index of vars for current phy link used by mst hub */
        k = *link_vars_start_index;
        /* set vars start index for next mst hub phy link */
        *link_vars_start_index += count;

        /* Try no compression */
        DRM_DEBUG_DRIVER("MST_DSC Try no compression\n");
        for (i = 0; i < count; i++) {
                vars[i + k].aconnector = params[i].aconnector;
                vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps, fec_overhead_multiplier_x1000);
                vars[i + k].dsc_enabled = false;
                vars[i + k].bpp_x16 = 0;
                ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port,
                                                    vars[i + k].pbn);
                if (ret < 0)
                        return ret;
        }
        ret = drm_dp_mst_atomic_check(state);
        if (ret == 0 && !debugfs_overwrite) {
                set_dsc_configs_from_fairness_vars(params, vars, count, k);
                return 0;
        } else if (ret != -ENOSPC) {
                return ret;
        }

        log_dsc_params(count, vars, k);

        /* Try max compression */
        DRM_DEBUG_DRIVER("MST_DSC Try max compression\n");
        for (i = 0; i < count; i++) {
                if (params[i].compression_possible && params[i].clock_force_enable != DSC_CLK_FORCE_DISABLE) {
                        vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps, fec_overhead_multiplier_x1000);
                        vars[i + k].dsc_enabled = true;
                        vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16;
                        ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr,
                                                            params[i].port, vars[i + k].pbn);
                        if (ret < 0)
                                return ret;
                } else {
                        vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps, fec_overhead_multiplier_x1000);
                        vars[i + k].dsc_enabled = false;
                        vars[i + k].bpp_x16 = 0;
                        ret = drm_dp_atomic_find_time_slots(state, params[i].port->mgr,
                                                            params[i].port, vars[i + k].pbn);
                        if (ret < 0)
                                return ret;
                }
        }
        ret = drm_dp_mst_atomic_check(state);
        if (ret != 0)
                return ret;

        log_dsc_params(count, vars, k);

        /* Optimize degree of compression */
        DRM_DEBUG_DRIVER("MST_DSC Try optimize compression\n");
        ret = increase_dsc_bpp(state, mst_state, dc_link, params, vars, count, k);
        if (ret < 0) {
                DRM_DEBUG_DRIVER("MST_DSC Failed to optimize compression\n");
                return ret;
        }

        log_dsc_params(count, vars, k);

        DRM_DEBUG_DRIVER("MST_DSC Try disable compression\n");
        ret = try_disable_dsc(state, dc_link, params, vars, count, k);
        if (ret < 0) {
                DRM_DEBUG_DRIVER("MST_DSC Failed to disable compression\n");
                return ret;
        }

        log_dsc_params(count, vars, k);

        set_dsc_configs_from_fairness_vars(params, vars, count, k);

        return 0;
}

static bool is_dsc_need_re_compute(
        struct drm_atomic_state *state,
        struct dc_state *dc_state,
        struct dc_link *dc_link)
{
        int i, j;
        bool is_dsc_need_re_compute = false;
        struct amdgpu_dm_connector *stream_on_link[MAX_PIPES];
        int new_stream_on_link_num = 0;
        struct amdgpu_dm_connector *aconnector;
        struct dc_stream_state *stream;
        const struct dc *dc = dc_link->dc;

        /* only check phy used by dsc mst branch */
        if (dc_link->type != dc_connection_mst_branch)
                goto out;

        /* add a check for older MST DSC with no virtual DPCDs */
        if (needs_dsc_aux_workaround(dc_link)  &&
                (!(dc_link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_SUPPORT ||
                dc_link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_PASSTHROUGH_SUPPORT)))
                goto out;

        for (i = 0; i < MAX_PIPES; i++)
                stream_on_link[i] = NULL;

        DRM_DEBUG_DRIVER("%s: MST_DSC check on %d streams in new dc_state\n", __func__, dc_state->stream_count);

        /* check if there is mode change in new request */
        for (i = 0; i < dc_state->stream_count; i++) {
                struct drm_crtc_state *new_crtc_state;
                struct drm_connector_state *new_conn_state;

                stream = dc_state->streams[i];
                if (!stream)
                        continue;

                DRM_DEBUG_DRIVER("%s:%d MST_DSC checking #%d stream 0x%p\n", __func__, __LINE__, i, stream);

                /* check if stream using the same link for mst */
                if (stream->link != dc_link)
                        continue;

                aconnector = (struct amdgpu_dm_connector *) stream->dm_stream_context;
                if (!aconnector)
                        continue;

                stream_on_link[new_stream_on_link_num] = aconnector;
                new_stream_on_link_num++;

                new_conn_state = drm_atomic_get_new_connector_state(state, &aconnector->base);
                if (!new_conn_state) {
                        DRM_DEBUG_DRIVER("%s:%d MST_DSC no new_conn_state for stream 0x%p, aconnector 0x%p\n",
                                         __func__, __LINE__, stream, aconnector);
                        continue;
                }

                if (IS_ERR(new_conn_state))
                        continue;

                if (!new_conn_state->crtc)
                        continue;

                new_crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
                if (!new_crtc_state) {
                        DRM_DEBUG_DRIVER("%s:%d MST_DSC no new_crtc_state for crtc of stream 0x%p, aconnector 0x%p\n",
                                                __func__, __LINE__, stream, aconnector);
                        continue;
                }

                if (IS_ERR(new_crtc_state))
                        continue;

                if (new_crtc_state->enable && new_crtc_state->active) {
                        if (new_crtc_state->mode_changed || new_crtc_state->active_changed ||
                                        new_crtc_state->connectors_changed) {
                                DRM_DEBUG_DRIVER("%s:%d MST_DSC dsc recompute required."
                                                 "stream 0x%p in new dc_state\n",
                                                 __func__, __LINE__, stream);
                                is_dsc_need_re_compute = true;
                                goto out;
                        }
                }
        }

        if (new_stream_on_link_num == 0) {
                DRM_DEBUG_DRIVER("%s:%d MST_DSC no mode change request for streams in new dc_state\n",
                                 __func__, __LINE__);
                is_dsc_need_re_compute = false;
                goto out;
        }

        DRM_DEBUG_DRIVER("%s: MST_DSC check on %d streams in current dc_state\n",
                         __func__, dc->current_state->stream_count);

        /* check current_state if there stream on link but it is not in
         * new request state
         */
        for (i = 0; i < dc->current_state->stream_count; i++) {
                stream = dc->current_state->streams[i];
                /* only check stream on the mst hub */
                if (stream->link != dc_link)
                        continue;

                aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
                if (!aconnector)
                        continue;

                for (j = 0; j < new_stream_on_link_num; j++) {
                        if (stream_on_link[j]) {
                                if (aconnector == stream_on_link[j])
                                        break;
                        }
                }

                if (j == new_stream_on_link_num) {
                        /* not in new state */
                        DRM_DEBUG_DRIVER("%s:%d MST_DSC dsc recompute required."
                                         "stream 0x%p in current dc_state but not in new dc_state\n",
                                                __func__, __LINE__, stream);
                        is_dsc_need_re_compute = true;
                        break;
                }
        }

out:
        DRM_DEBUG_DRIVER("%s: MST_DSC dsc recompute %s\n",
                         __func__, is_dsc_need_re_compute ? "required" : "not required");

        return is_dsc_need_re_compute;
}

int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
                                      struct dc_state *dc_state,
                                      struct dsc_mst_fairness_vars *vars)
{
        int i, j;
        struct dc_stream_state *stream;
        bool computed_streams[MAX_PIPES];
        struct amdgpu_dm_connector *aconnector;
        struct drm_dp_mst_topology_mgr *mst_mgr;
        struct resource_pool *res_pool;
        int link_vars_start_index = 0;
        int ret = 0;

        for (i = 0; i < dc_state->stream_count; i++)
                computed_streams[i] = false;

        for (i = 0; i < dc_state->stream_count; i++) {
                stream = dc_state->streams[i];
                res_pool = stream->ctx->dc->res_pool;

                if (stream->signal != SIGNAL_TYPE_DISPLAY_PORT_MST)
                        continue;

                aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;

                DRM_DEBUG_DRIVER("%s: MST_DSC compute mst dsc configs for stream 0x%p, aconnector 0x%p\n",
                                __func__, stream, aconnector);

                if (!aconnector || !aconnector->dc_sink || !aconnector->mst_output_port)
                        continue;

                if (!aconnector->dc_sink->dsc_caps.dsc_dec_caps.is_dsc_supported)
                        continue;

                if (computed_streams[i])
                        continue;

                if (res_pool->funcs->remove_stream_from_ctx &&
                    res_pool->funcs->remove_stream_from_ctx(stream->ctx->dc, dc_state, stream) != DC_OK)
                        return -EINVAL;

                if (!is_dsc_need_re_compute(state, dc_state, stream->link))
                        continue;

                mst_mgr = aconnector->mst_output_port->mgr;
                ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, mst_mgr,
                                                       &link_vars_start_index);
                if (ret != 0)
                        return ret;

                for (j = 0; j < dc_state->stream_count; j++) {
                        if (dc_state->streams[j]->link == stream->link)
                                computed_streams[j] = true;
                }
        }

        for (i = 0; i < dc_state->stream_count; i++) {
                stream = dc_state->streams[i];

                if (stream->timing.flags.DSC == 1)
                        if (dc_stream_add_dsc_to_resource(stream->ctx->dc, dc_state, stream) != DC_OK) {
                                DRM_DEBUG_DRIVER("%s:%d MST_DSC Failed to request dsc hw resource for stream 0x%p\n",
                                                        __func__, __LINE__, stream);
                                return -EINVAL;
                        }
        }

        return ret;
}

static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
                                                 struct dc_state *dc_state,
                                                 struct dsc_mst_fairness_vars *vars)
{
        int i, j;
        struct dc_stream_state *stream;
        bool computed_streams[MAX_PIPES];
        struct amdgpu_dm_connector *aconnector;
        struct drm_dp_mst_topology_mgr *mst_mgr;
        int link_vars_start_index = 0;
        int ret = 0;

        for (i = 0; i < dc_state->stream_count; i++)
                computed_streams[i] = false;

        for (i = 0; i < dc_state->stream_count; i++) {
                stream = dc_state->streams[i];

                if (stream->signal != SIGNAL_TYPE_DISPLAY_PORT_MST)
                        continue;

                aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;

                DRM_DEBUG_DRIVER("MST_DSC pre compute mst dsc configs for #%d stream 0x%p, aconnector 0x%p\n",
                                        i, stream, aconnector);

                if (!aconnector || !aconnector->dc_sink || !aconnector->mst_output_port)
                        continue;

                if (!aconnector->dc_sink->dsc_caps.dsc_dec_caps.is_dsc_supported)
                        continue;

                if (computed_streams[i])
                        continue;

                if (!is_dsc_need_re_compute(state, dc_state, stream->link))
                        continue;

                mst_mgr = aconnector->mst_output_port->mgr;
                ret = compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars, mst_mgr,
                                                       &link_vars_start_index);
                if (ret != 0)
                        return ret;

                for (j = 0; j < dc_state->stream_count; j++) {
                        if (dc_state->streams[j]->link == stream->link)
                                computed_streams[j] = true;
                }
        }

        return ret;
}

static int find_crtc_index_in_state_by_stream(struct drm_atomic_state *state,
                                              struct dc_stream_state *stream)
{
        int i;
        struct drm_crtc *crtc;
        struct drm_crtc_state *new_state, *old_state;

        for_each_oldnew_crtc_in_state(state, crtc, old_state, new_state, i) {
                struct dm_crtc_state *dm_state = to_dm_crtc_state(new_state);

                if (dm_state->stream == stream)
                        return i;
        }
        return -1;
}

static bool is_link_to_dschub(struct dc_link *dc_link)
{
        union dpcd_dsc_basic_capabilities *dsc_caps =
                        &dc_link->dpcd_caps.dsc_caps.dsc_basic_caps;

        /* only check phy used by dsc mst branch */
        if (dc_link->type != dc_connection_mst_branch)
                return false;

        if (!(dsc_caps->fields.dsc_support.DSC_SUPPORT ||
              dsc_caps->fields.dsc_support.DSC_PASSTHROUGH_SUPPORT))
                return false;
        return true;
}

static bool is_dsc_precompute_needed(struct drm_atomic_state *state)
{
        int i;
        struct drm_crtc *crtc;
        struct drm_crtc_state *old_crtc_state, *new_crtc_state;
        bool ret = false;

        for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
                struct dm_crtc_state *dm_crtc_state = to_dm_crtc_state(new_crtc_state);

                if (!amdgpu_dm_find_first_crtc_matching_connector(state, crtc)) {
                        ret =  false;
                        break;
                }
                if (dm_crtc_state->stream && dm_crtc_state->stream->link)
                        if (is_link_to_dschub(dm_crtc_state->stream->link))
                                ret = true;
        }
        return ret;
}

int pre_validate_dsc(struct drm_atomic_state *state,
                     struct dm_atomic_state **dm_state_ptr,
                     struct dsc_mst_fairness_vars *vars)
{
        int i;
        struct dm_atomic_state *dm_state;
        struct dc_state *local_dc_state = NULL;
        int ret = 0;

        if (!is_dsc_precompute_needed(state)) {
                DRM_INFO_ONCE("%s:%d MST_DSC dsc precompute is not needed\n", __func__, __LINE__);
                return 0;
        }
        ret = dm_atomic_get_state(state, dm_state_ptr);
        if (ret != 0) {
                DRM_INFO_ONCE("%s:%d MST_DSC dm_atomic_get_state() failed\n", __func__, __LINE__);
                return ret;
        }
        dm_state = *dm_state_ptr;

        /*
         * create local vailable for dc_state. copy content of streams of dm_state->context
         * to local variable. make sure stream pointer of local variable not the same as stream
         * from dm_state->context.
         */

        local_dc_state = vmalloc(sizeof(struct dc_state));
        if (!local_dc_state)
                return -ENOMEM;
        memcpy(local_dc_state, dm_state->context, sizeof(struct dc_state));

        for (i = 0; i < local_dc_state->stream_count; i++) {
                struct dc_stream_state *stream = dm_state->context->streams[i];
                int ind = find_crtc_index_in_state_by_stream(state, stream);

                if (ind >= 0) {
                        struct drm_connector *connector;
                        struct drm_connector_state *drm_new_conn_state;
                        struct dm_connector_state *dm_new_conn_state;
                        struct dm_crtc_state *dm_old_crtc_state;

                        connector =
                                amdgpu_dm_find_first_crtc_matching_connector(state,
                                                                             state->crtcs[ind].ptr);
                        if (!connector)
                                continue;

                        drm_new_conn_state =
                                drm_atomic_get_new_connector_state(state,
                                                                   connector);
                        dm_new_conn_state = to_dm_connector_state(drm_new_conn_state);
                        dm_old_crtc_state = to_dm_crtc_state(state->crtcs[ind].old_state);

                        local_dc_state->streams[i] =
                                create_validate_stream_for_sink(connector,
                                                                &state->crtcs[ind].new_state->mode,
                                                                dm_new_conn_state,
                                                                dm_old_crtc_state->stream);
                        if (local_dc_state->streams[i] == NULL) {
                                ret = -EINVAL;
                                break;
                        }
                }
        }

        if (ret != 0)
                goto clean_exit;

        ret = pre_compute_mst_dsc_configs_for_state(state, local_dc_state, vars);
        if (ret != 0) {
                DRM_INFO_ONCE("%s:%d MST_DSC dsc pre_compute_mst_dsc_configs_for_state() failed\n",
                                __func__, __LINE__);
                ret = -EINVAL;
                goto clean_exit;
        }

        /*
         * compare local_streams -> timing  with dm_state->context,
         * if the same set crtc_state->mode-change = 0;
         */
        for (i = 0; i < local_dc_state->stream_count; i++) {
                struct dc_stream_state *stream = dm_state->context->streams[i];

                if (local_dc_state->streams[i] &&
                    dc_is_timing_changed(stream, local_dc_state->streams[i])) {
                        DRM_INFO_ONCE("%s:%d MST_DSC crtc[%d] needs mode_change\n", __func__, __LINE__, i);
                } else {
                        int ind = find_crtc_index_in_state_by_stream(state, stream);

                        if (ind >= 0) {
                                struct dm_crtc_state *dm_new_crtc_state = to_dm_crtc_state(state->crtcs[ind].new_state);

                                DRM_INFO_ONCE("%s:%d MST_DSC no mode changed for stream 0x%p\n",
                                                __func__, __LINE__, stream);
                                dm_new_crtc_state->base.mode_changed = dm_new_crtc_state->mode_changed_independent_from_dsc;
                        }
                }
        }
clean_exit:
        for (i = 0; i < local_dc_state->stream_count; i++) {
                struct dc_stream_state *stream = dm_state->context->streams[i];

                if (local_dc_state->streams[i] != stream)
                        dc_stream_release(local_dc_state->streams[i]);
        }

        vfree(local_dc_state);

        return ret;
}

static uint32_t kbps_from_pbn(unsigned int pbn)
{
        uint64_t kbps = (uint64_t)pbn;

        kbps *= (1000000 / PEAK_FACTOR_X1000);
        kbps *= 8;
        kbps *= 54;
        kbps /= 64;

        return (uint32_t)kbps;
}

static bool is_dsc_common_config_possible(struct dc_stream_state *stream,
                                          struct dc_dsc_bw_range *bw_range)
{
        struct dc_dsc_policy dsc_policy = {0};
        bool is_dsc_possible;

        dc_dsc_get_policy_for_timing(&stream->timing, 0, &dsc_policy, dc_link_get_highest_encoding_format(stream->link));
        is_dsc_possible = dc_dsc_compute_bandwidth_range(stream->sink->ctx->dc->res_pool->dscs[0],
                                                         stream->sink->ctx->dc->debug.dsc_min_slice_height_override,
                                                         dsc_policy.min_target_bpp * 16,
                                                         dsc_policy.max_target_bpp * 16,
                                                         &stream->sink->dsc_caps.dsc_dec_caps,
                                                         &stream->timing, dc_link_get_highest_encoding_format(stream->link), bw_range);

        return is_dsc_possible;
}
#endif

#if defined(CONFIG_DRM_AMD_DC_FP)
static bool dp_get_link_current_set_bw(struct drm_dp_aux *aux, uint32_t *cur_link_bw)
{
        uint32_t total_data_bw_efficiency_x10000 = 0;
        uint32_t link_rate_per_lane_kbps = 0;
        enum dc_link_rate link_rate;
        union lane_count_set lane_count;
        u8 dp_link_encoding;
        u8 link_bw_set = 0;
        u8 data[16] = {0};

        *cur_link_bw = 0;

        if (drm_dp_dpcd_read(aux, DP_LINK_BW_SET, data, 16) != 16)
                return false;

        dp_link_encoding = data[DP_MAIN_LINK_CHANNEL_CODING_SET - DP_LINK_BW_SET];
        link_bw_set = data[DP_LINK_BW_SET - DP_LINK_BW_SET];
        lane_count.raw = data[DP_LANE_COUNT_SET - DP_LINK_BW_SET];

        drm_dbg_dp(aux->drm_dev, "MST_DSC downlink setting: %d, 0x%x x %d\n",
                   dp_link_encoding, link_bw_set, lane_count.bits.LANE_COUNT_SET);

        switch (dp_link_encoding) {
        case DP_8b_10b_ENCODING:
                link_rate = link_bw_set;
                link_rate_per_lane_kbps = link_rate * LINK_RATE_REF_FREQ_IN_KHZ * BITS_PER_DP_BYTE;
                total_data_bw_efficiency_x10000 = DATA_EFFICIENCY_8b_10b_x10000;
                total_data_bw_efficiency_x10000 /= 100;
                total_data_bw_efficiency_x10000 *= DATA_EFFICIENCY_8b_10b_FEC_EFFICIENCY_x100;
                break;
        case DP_128b_132b_ENCODING:
                switch (link_bw_set) {
                case DP_LINK_BW_10:
                        link_rate = LINK_RATE_UHBR10;
                        break;
                case DP_LINK_BW_13_5:
                        link_rate = LINK_RATE_UHBR13_5;
                        break;
                case DP_LINK_BW_20:
                        link_rate = LINK_RATE_UHBR20;
                        break;
                default:
                        return false;
                }

                link_rate_per_lane_kbps = link_rate * 10000;
                total_data_bw_efficiency_x10000 = DATA_EFFICIENCY_128b_132b_x10000;
                break;
        default:
                return false;
        }

        *cur_link_bw = link_rate_per_lane_kbps * lane_count.bits.LANE_COUNT_SET / 10000 * total_data_bw_efficiency_x10000;
        return true;
}
#endif

enum dc_status dm_dp_mst_is_port_support_mode(
        struct amdgpu_dm_connector *aconnector,
        struct dc_stream_state *stream)
{
#if defined(CONFIG_DRM_AMD_DC_FP)
        int branch_max_throughput_mps = 0;
        struct dc_link_settings cur_link_settings;
        uint32_t end_to_end_bw_in_kbps = 0;
        uint32_t root_link_bw_in_kbps = 0;
        uint32_t virtual_channel_bw_in_kbps = 0;
        struct dc_dsc_bw_range bw_range = {0};
        struct dc_dsc_config_options dsc_options = {0};
        uint32_t stream_kbps;

        /* DSC unnecessary case
         * Check if timing could be supported within end-to-end BW
         */
        stream_kbps =
                dc_bandwidth_in_kbps_from_timing(&stream->timing,
                        dc_link_get_highest_encoding_format(stream->link));
        cur_link_settings = stream->link->verified_link_cap;
        root_link_bw_in_kbps = dc_link_bandwidth_kbps(aconnector->dc_link, &cur_link_settings);
        virtual_channel_bw_in_kbps = kbps_from_pbn(aconnector->mst_output_port->full_pbn);

        /* pick the end to end bw bottleneck */
        end_to_end_bw_in_kbps = min(root_link_bw_in_kbps, virtual_channel_bw_in_kbps);

        if (stream_kbps <= end_to_end_bw_in_kbps) {
                DRM_DEBUG_DRIVER("MST_DSC no dsc required. End-to-end bw sufficient\n");
                return DC_OK;
        }

        /*DSC necessary case*/
        if (!aconnector->dsc_aux)
                return DC_FAIL_BANDWIDTH_VALIDATE;

        if (is_dsc_common_config_possible(stream, &bw_range)) {

                /*capable of dsc passthough. dsc bitstream along the entire path*/
                if (aconnector->mst_output_port->passthrough_aux) {
                        if (bw_range.min_kbps > end_to_end_bw_in_kbps) {
                                DRM_DEBUG_DRIVER("MST_DSC dsc passthrough and decode at endpoint"
                                                 "Max dsc compression bw can't fit into end-to-end bw\n");
                                return DC_FAIL_BANDWIDTH_VALIDATE;
                        }
                } else {
                        /*dsc bitstream decoded at the dp last link*/
                        struct drm_dp_mst_port *immediate_upstream_port = NULL;
                        uint32_t end_link_bw = 0;

                        /*Get last DP link BW capability. Mode shall be supported by Legacy peer*/
                        if (aconnector->mst_output_port->pdt != DP_PEER_DEVICE_DP_LEGACY_CONV &&
                                aconnector->mst_output_port->pdt != DP_PEER_DEVICE_NONE) {
                                if (aconnector->vc_full_pbn != aconnector->mst_output_port->full_pbn) {
                                        dp_get_link_current_set_bw(&aconnector->mst_output_port->aux, &end_link_bw);
                                        aconnector->vc_full_pbn = aconnector->mst_output_port->full_pbn;
                                        aconnector->mst_local_bw = end_link_bw;
                                } else {
                                        end_link_bw = aconnector->mst_local_bw;
                                }

                                if (end_link_bw > 0 &&
                                    stream_kbps > end_link_bw &&
                                    aconnector->branch_ieee_oui != DP_BRANCH_DEVICE_ID_90CC24) {
                                        DRM_DEBUG_DRIVER("MST_DSC dsc decode at last link. "
                                                         "Mode required bw can't fit into last link\n");
                                        return DC_FAIL_BANDWIDTH_VALIDATE;
                                }
                        }

                        /*Get virtual channel bandwidth between source and the link before the last link*/
                        if (aconnector->mst_output_port->parent->port_parent)
                                immediate_upstream_port = aconnector->mst_output_port->parent->port_parent;

                        if (immediate_upstream_port) {
                                virtual_channel_bw_in_kbps = kbps_from_pbn(immediate_upstream_port->full_pbn);
                                virtual_channel_bw_in_kbps = min(root_link_bw_in_kbps, virtual_channel_bw_in_kbps);
                        } else {
                                /* For topology LCT 1 case - only one mstb*/
                                virtual_channel_bw_in_kbps = root_link_bw_in_kbps;
                        }

                        if (bw_range.min_kbps > virtual_channel_bw_in_kbps) {
                                DRM_DEBUG_DRIVER("MST_DSC dsc decode at last link."
                                                 "Max dsc compression can't fit into MST available bw\n");
                                return DC_FAIL_BANDWIDTH_VALIDATE;
                        }
                }

                /*Confirm if we can obtain dsc config*/
                dc_dsc_get_default_config_option(stream->link->dc, &dsc_options);
                dsc_options.max_target_bpp_limit_override_x16 = aconnector->base.display_info.max_dsc_bpp * 16;
                if (dc_dsc_compute_config(stream->sink->ctx->dc->res_pool->dscs[0],
                                &stream->sink->dsc_caps.dsc_dec_caps,
                                &dsc_options,
                                end_to_end_bw_in_kbps,
                                &stream->timing,
                                dc_link_get_highest_encoding_format(stream->link),
                                &stream->timing.dsc_cfg)) {
                        stream->timing.flags.DSC = 1;
                        DRM_DEBUG_DRIVER("MST_DSC require dsc and dsc config found\n");
                } else {
                        DRM_DEBUG_DRIVER("MST_DSC require dsc but can't find appropriate dsc config\n");
                        return DC_FAIL_BANDWIDTH_VALIDATE;
                }

                /* check is mst dsc output bandwidth branch_overall_throughput_0_mps */
                switch (stream->timing.pixel_encoding) {
                case PIXEL_ENCODING_RGB:
                case PIXEL_ENCODING_YCBCR444:
                        branch_max_throughput_mps =
                                aconnector->dc_sink->dsc_caps.dsc_dec_caps.branch_overall_throughput_0_mps;
                        break;
                case PIXEL_ENCODING_YCBCR422:
                case PIXEL_ENCODING_YCBCR420:
                        branch_max_throughput_mps =
                                aconnector->dc_sink->dsc_caps.dsc_dec_caps.branch_overall_throughput_1_mps;
                        break;
                default:
                        break;
                }

                if (branch_max_throughput_mps != 0 &&
                        ((stream->timing.pix_clk_100hz / 10) >  branch_max_throughput_mps * 1000)) {
                        DRM_DEBUG_DRIVER("MST_DSC require dsc but max throughput mps fails\n");
                        return DC_FAIL_BANDWIDTH_VALIDATE;
                }
        } else {
                DRM_DEBUG_DRIVER("MST_DSC require dsc but can't find common dsc config\n");
                return DC_FAIL_BANDWIDTH_VALIDATE;
        }
#endif
        return DC_OK;
}