/* * drm_irq.c IRQ and vblank support * * \author Rickard E. (Rik) Faith <faith@valinux.com> * \author Gareth Hughes <gareth@valinux.com> * * 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 (including the next * paragraph) 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 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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. */ #include <linux/export.h> #include <linux/kthread.h> #include <linux/moduleparam.h> #include <drm/drm_crtc.h> #include <drm/drm_drv.h> #include <drm/drm_framebuffer.h> #include <drm/drm_managed.h> #include <drm/drm_modeset_helper_vtables.h> #include <drm/drm_print.h> #include <drm/drm_vblank.h> #include "drm_internal.h" #include "drm_trace.h" /** * DOC: vblank handling * * From the computer's perspective, every time the monitor displays * a new frame the scanout engine has "scanned out" the display image * from top to bottom, one row of pixels at a time. The current row * of pixels is referred to as the current scanline. * * In addition to the display's visible area, there's usually a couple of * extra scanlines which aren't actually displayed on the screen. * These extra scanlines don't contain image data and are occasionally used * for features like audio and infoframes. The region made up of these * scanlines is referred to as the vertical blanking region, or vblank for * short. * * For historical reference, the vertical blanking period was designed to * give the electron gun (on CRTs) enough time to move back to the top of * the screen to start scanning out the next frame. Similar for horizontal * blanking periods. They were designed to give the electron gun enough * time to move back to the other side of the screen to start scanning the * next scanline. * * :: * * * physical → ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽ * top of | | * display | | * | New frame | * | | * |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓| * |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| ← Scanline, * |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓| updates the * | | frame as it * | | travels down * | | ("scan out") * | Old frame | * | | * | | * | | * | | physical * | | bottom of * vertical |⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽| ← display * blanking ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆ * region → ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆ * ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆ * start of → ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽ * new frame * * "Physical top of display" is the reference point for the high-precision/ * corrected timestamp. * * On a lot of display hardware, programming needs to take effect during the * vertical blanking period so that settings like gamma, the image buffer * buffer to be scanned out, etc. can safely be changed without showing * any visual artifacts on the screen. In some unforgiving hardware, some of * this programming has to both start and end in the same vblank. To help * with the timing of the hardware programming, an interrupt is usually * available to notify the driver when it can start the updating of registers. * The interrupt is in this context named the vblank interrupt. * * The vblank interrupt may be fired at different points depending on the * hardware. Some hardware implementations will fire the interrupt when the * new frame start, other implementations will fire the interrupt at different * points in time. * * Vertical blanking plays a major role in graphics rendering. To achieve * tear-free display, users must synchronize page flips and/or rendering to * vertical blanking. The DRM API offers ioctls to perform page flips * synchronized to vertical blanking and wait for vertical blanking. * * The DRM core handles most of the vertical blanking management logic, which * involves filtering out spurious interrupts, keeping race-free blanking * counters, coping with counter wrap-around and resets and keeping use counts. * It relies on the driver to generate vertical blanking interrupts and * optionally provide a hardware vertical blanking counter. * * Drivers must initialize the vertical blanking handling core with a call to * drm_vblank_init(). Minimally, a driver needs to implement * &drm_crtc_funcs.enable_vblank and &drm_crtc_funcs.disable_vblank plus call * drm_crtc_handle_vblank() in its vblank interrupt handler for working vblank * support. * * Vertical blanking interrupts can be enabled by the DRM core or by drivers * themselves (for instance to handle page flipping operations). The DRM core * maintains a vertical blanking use count to ensure that the interrupts are not * disabled while a user still needs them. To increment the use count, drivers * call drm_crtc_vblank_get() and release the vblank reference again with * drm_crtc_vblank_put(). In between these two calls vblank interrupts are * guaranteed to be enabled. * * On many hardware disabling the vblank interrupt cannot be done in a race-free * manner, see &drm_vblank_crtc_config.disable_immediate and * &drm_driver.max_vblank_count. In that case the vblank core only disables the * vblanks after a timer has expired, which can be configured through the * ``vblankoffdelay`` module parameter. * * Drivers for hardware without support for vertical-blanking interrupts * must not call drm_vblank_init(). For such drivers, atomic helpers will * automatically generate fake vblank events as part of the display update. * This functionality also can be controlled by the driver by enabling and * disabling struct drm_crtc_state.no_vblank. */ /* Retry timestamp calculation up to 3 times to satisfy * drm_timestamp_precision before giving up. */ #define DRM_TIMESTAMP_MAXRETRIES 3 /* Threshold in nanoseconds for detection of redundant * vblank irq in drm_handle_vblank(). 1 msec should be ok. */ #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 static bool drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe, ktime_t *tvblank, bool in_vblank_irq); static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */ static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */ module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600); module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600); MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)"); MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]"); static struct drm_vblank_crtc * drm_vblank_crtc(struct drm_device *dev, unsigned int pipe) { return &dev->vblank[pipe]; } struct drm_vblank_crtc * drm_crtc_vblank_crtc(struct drm_crtc *crtc) { return drm_vblank_crtc(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_crtc); static void store_vblank(struct drm_device *dev, unsigned int pipe, u32 vblank_count_inc, ktime_t t_vblank, u32 last) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); assert_spin_locked(&dev->vblank_time_lock); vblank->last = last; write_seqlock(&vblank->seqlock); vblank->time = t_vblank; atomic64_add(vblank_count_inc, &vblank->count); write_sequnlock(&vblank->seqlock); } static u32 drm_max_vblank_count(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); return vblank->max_vblank_count ?: dev->max_vblank_count; } /* * "No hw counter" fallback implementation of .get_vblank_counter() hook, * if there is no usable hardware frame counter available. */ static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe) { drm_WARN_ON_ONCE(dev, drm_max_vblank_count(dev, pipe) != 0); return 0; } static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe) { if (drm_core_check_feature(dev, DRIVER_MODESET)) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); if (drm_WARN_ON(dev, !crtc)) return 0; if (crtc->funcs->get_vblank_counter) return crtc->funcs->get_vblank_counter(crtc); } return drm_vblank_no_hw_counter(dev, pipe); } /* * Reset the stored timestamp for the current vblank count to correspond * to the last vblank occurred. * * Only to be called from drm_crtc_vblank_on(). * * Note: caller must hold &drm_device.vbl_lock since this reads & writes * device vblank fields. */ static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe) { u32 cur_vblank; bool rc; ktime_t t_vblank; int count = DRM_TIMESTAMP_MAXRETRIES; spin_lock(&dev->vblank_time_lock); /* * sample the current counter to avoid random jumps * when drm_vblank_enable() applies the diff */ do { cur_vblank = __get_vblank_counter(dev, pipe); rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false); } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0); /* * Only reinitialize corresponding vblank timestamp if high-precision query * available and didn't fail. Otherwise reinitialize delayed at next vblank * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid. */ if (!rc) t_vblank = 0; /* * +1 to make sure user will never see the same * vblank counter value before and after a modeset */ store_vblank(dev, pipe, 1, t_vblank, cur_vblank); spin_unlock(&dev->vblank_time_lock); } /* * Call back into the driver to update the appropriate vblank counter * (specified by @pipe). Deal with wraparound, if it occurred, and * update the last read value so we can deal with wraparound on the next * call if necessary. * * Only necessary when going from off->on, to account for frames we * didn't get an interrupt for. * * Note: caller must hold &drm_device.vbl_lock since this reads & writes * device vblank fields. */ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe, bool in_vblank_irq) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); u32 cur_vblank, diff; bool rc; ktime_t t_vblank; int count = DRM_TIMESTAMP_MAXRETRIES; int framedur_ns = vblank->framedur_ns; u32 max_vblank_count = drm_max_vblank_count(dev, pipe); /* * Interrupts were disabled prior to this call, so deal with counter * wrap if needed. * NOTE! It's possible we lost a full dev->max_vblank_count + 1 events * here if the register is small or we had vblank interrupts off for * a long time. * * We repeat the hardware vblank counter & timestamp query until * we get consistent results. This to prevent races between gpu * updating its hardware counter while we are retrieving the * corresponding vblank timestamp. */ do { cur_vblank = __get_vblank_counter(dev, pipe); rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq); } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0); if (max_vblank_count) { /* trust the hw counter when it's around */ diff = (cur_vblank - vblank->last) & max_vblank_count; } else if (rc && framedur_ns) { u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time)); /* * Figure out how many vblanks we've missed based * on the difference in the timestamps and the * frame/field duration. */ drm_dbg_vbl(dev, "crtc %u: Calculating number of vblanks." " diff_ns = %lld, framedur_ns = %d)\n", pipe, (long long)diff_ns, framedur_ns); diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns); if (diff == 0 && in_vblank_irq) drm_dbg_vbl(dev, "crtc %u: Redundant vblirq ignored\n", pipe); } else { /* some kind of default for drivers w/o accurate vbl timestamping */ diff = in_vblank_irq ? 1 : 0; } /* * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset * interval? If so then vblank irqs keep running and it will likely * happen that the hardware vblank counter is not trustworthy as it * might reset at some point in that interval and vblank timestamps * are not trustworthy either in that interval. Iow. this can result * in a bogus diff >> 1 which must be avoided as it would cause * random large forward jumps of the software vblank counter. */ if (diff > 1 && (vblank->inmodeset & 0x2)) { drm_dbg_vbl(dev, "clamping vblank bump to 1 on crtc %u: diffr=%u" " due to pre-modeset.\n", pipe, diff); diff = 1; } drm_dbg_vbl(dev, "updating vblank count on crtc %u:" " current=%llu, diff=%u, hw=%u hw_last=%u\n", pipe, (unsigned long long)atomic64_read(&vblank->count), diff, cur_vblank, vblank->last); if (diff == 0) { drm_WARN_ON_ONCE(dev, cur_vblank != vblank->last); return; } /* * Only reinitialize corresponding vblank timestamp if high-precision query * available and didn't fail, or we were called from the vblank interrupt. * Otherwise reinitialize delayed at next vblank interrupt and assign 0 * for now, to mark the vblanktimestamp as invalid. */ if (!rc && !in_vblank_irq) t_vblank = 0; store_vblank(dev, pipe, diff, t_vblank, cur_vblank); } u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); u64 count; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return 0; count = atomic64_read(&vblank->count); /* * This read barrier corresponds to the implicit write barrier of the * write seqlock in store_vblank(). Note that this is the only place * where we need an explicit barrier, since all other access goes * through drm_vblank_count_and_time(), which already has the required * read barrier curtesy of the read seqlock. */ smp_rmb(); return count; } /** * drm_crtc_accurate_vblank_count - retrieve the master vblank counter * @crtc: which counter to retrieve * * This function is similar to drm_crtc_vblank_count() but this function * interpolates to handle a race with vblank interrupts using the high precision * timestamping support. * * This is mostly useful for hardware that can obtain the scanout position, but * doesn't have a hardware frame counter. */ u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); u64 vblank; unsigned long flags; drm_WARN_ONCE(dev, drm_debug_enabled(DRM_UT_VBL) && !crtc->funcs->get_vblank_timestamp, "This function requires support for accurate vblank timestamps."); spin_lock_irqsave(&dev->vblank_time_lock, flags); drm_update_vblank_count(dev, pipe, false); vblank = drm_vblank_count(dev, pipe); spin_unlock_irqrestore(&dev->vblank_time_lock, flags); return vblank; } EXPORT_SYMBOL(drm_crtc_accurate_vblank_count); static void __disable_vblank(struct drm_device *dev, unsigned int pipe) { if (drm_core_check_feature(dev, DRIVER_MODESET)) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); if (drm_WARN_ON(dev, !crtc)) return; if (crtc->funcs->disable_vblank) crtc->funcs->disable_vblank(crtc); } } /* * Disable vblank irq's on crtc, make sure that last vblank count * of hardware and corresponding consistent software vblank counter * are preserved, even if there are any spurious vblank irq's after * disable. */ void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); unsigned long irqflags; assert_spin_locked(&dev->vbl_lock); /* Prevent vblank irq processing while disabling vblank irqs, * so no updates of timestamps or count can happen after we've * disabled. Needed to prevent races in case of delayed irq's. */ spin_lock_irqsave(&dev->vblank_time_lock, irqflags); /* * Update vblank count and disable vblank interrupts only if the * interrupts were enabled. This avoids calling the ->disable_vblank() * operation in atomic context with the hardware potentially runtime * suspended. */ if (!vblank->enabled) goto out; /* * Update the count and timestamp to maintain the * appearance that the counter has been ticking all along until * this time. This makes the count account for the entire time * between drm_crtc_vblank_on() and drm_crtc_vblank_off(). */ drm_update_vblank_count(dev, pipe, false); __disable_vblank(dev, pipe); vblank->enabled = false; out: spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); } static void vblank_disable_fn(void *arg) { struct drm_vblank_crtc *vblank = arg; struct drm_device *dev = vblank->dev; unsigned int pipe = vblank->pipe; unsigned long irqflags; spin_lock_irqsave(&dev->vbl_lock, irqflags); if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) { drm_dbg_core(dev, "disabling vblank on crtc %u\n", pipe); drm_vblank_disable_and_save(dev, pipe); } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } static void drm_vblank_init_release(struct drm_device *dev, void *ptr) { struct drm_vblank_crtc *vblank = ptr; drm_WARN_ON(dev, READ_ONCE(vblank->enabled) && drm_core_check_feature(dev, DRIVER_MODESET)); drm_vblank_destroy_worker(vblank); timer_delete_sync(&vblank->disable_timer); } /** * drm_vblank_init - initialize vblank support * @dev: DRM device * @num_crtcs: number of CRTCs supported by @dev * * This function initializes vblank support for @num_crtcs display pipelines. * Cleanup is handled automatically through a cleanup function added with * drmm_add_action_or_reset(). * * Returns: * Zero on success or a negative error code on failure. */ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs) { int ret; unsigned int i; mtx_init(&dev->vbl_lock, IPL_TTY); mtx_init(&dev->vblank_time_lock, IPL_TTY); dev->vblank = drmm_kcalloc(dev, num_crtcs, sizeof(*dev->vblank), GFP_KERNEL); if (!dev->vblank) return -ENOMEM; dev->num_crtcs = num_crtcs; for (i = 0; i < num_crtcs; i++) { struct drm_vblank_crtc *vblank = &dev->vblank[i]; vblank->dev = dev; vblank->pipe = i; init_waitqueue_head(&vblank->queue); #ifdef __linux__ timer_setup(&vblank->disable_timer, vblank_disable_fn, 0); #else timeout_set(&vblank->disable_timer, vblank_disable_fn, vblank); #endif seqlock_init(&vblank->seqlock, IPL_TTY); ret = drmm_add_action_or_reset(dev, drm_vblank_init_release, vblank); if (ret) return ret; ret = drm_vblank_worker_init(vblank); if (ret) return ret; } return 0; } EXPORT_SYMBOL(drm_vblank_init); /** * drm_dev_has_vblank - test if vblanking has been initialized for * a device * @dev: the device * * Drivers may call this function to test if vblank support is * initialized for a device. For most hardware this means that vblanking * can also be enabled. * * Atomic helpers use this function to initialize * &drm_crtc_state.no_vblank. See also drm_atomic_helper_check_modeset(). * * Returns: * True if vblanking has been initialized for the given device, false * otherwise. */ bool drm_dev_has_vblank(const struct drm_device *dev) { return dev->num_crtcs != 0; } EXPORT_SYMBOL(drm_dev_has_vblank); /** * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC * @crtc: which CRTC's vblank waitqueue to retrieve * * This function returns a pointer to the vblank waitqueue for the CRTC. * Drivers can use this to implement vblank waits using wait_event() and related * functions. */ wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc) { return &crtc->dev->vblank[drm_crtc_index(crtc)].queue; } EXPORT_SYMBOL(drm_crtc_vblank_waitqueue); /** * drm_calc_timestamping_constants - calculate vblank timestamp constants * @crtc: drm_crtc whose timestamp constants should be updated. * @mode: display mode containing the scanout timings * * Calculate and store various constants which are later needed by vblank and * swap-completion timestamping, e.g, by * drm_crtc_vblank_helper_get_vblank_timestamp(). They are derived from * CRTC's true scanout timing, so they take things like panel scaling or * other adjustments into account. */ void drm_calc_timestamping_constants(struct drm_crtc *crtc, const struct drm_display_mode *mode) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); int linedur_ns = 0, framedur_ns = 0; int dotclock = mode->crtc_clock; if (!drm_dev_has_vblank(dev)) return; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; /* Valid dotclock? */ if (dotclock > 0) { int frame_size = mode->crtc_htotal * mode->crtc_vtotal; /* * Convert scanline length in pixels and video * dot clock to line duration and frame duration * in nanoseconds: */ linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock); framedur_ns = div_u64((u64) frame_size * 1000000, dotclock); /* * Fields of interlaced scanout modes are only half a frame duration. */ if (mode->flags & DRM_MODE_FLAG_INTERLACE) framedur_ns /= 2; } else { drm_err(dev, "crtc %u: Can't calculate constants, dotclock = 0!\n", crtc->base.id); } vblank->linedur_ns = linedur_ns; vblank->framedur_ns = framedur_ns; drm_mode_copy(&vblank->hwmode, mode); drm_dbg_core(dev, "crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n", crtc->base.id, mode->crtc_htotal, mode->crtc_vtotal, mode->crtc_vdisplay); drm_dbg_core(dev, "crtc %u: clock %d kHz framedur %d linedur %d\n", crtc->base.id, dotclock, framedur_ns, linedur_ns); } EXPORT_SYMBOL(drm_calc_timestamping_constants); /** * drm_crtc_vblank_helper_get_vblank_timestamp_internal - precise vblank * timestamp helper * @crtc: CRTC whose vblank timestamp to retrieve * @max_error: Desired maximum allowable error in timestamps (nanosecs) * On return contains true maximum error of timestamp * @vblank_time: Pointer to time which should receive the timestamp * @in_vblank_irq: * True when called from drm_crtc_handle_vblank(). Some drivers * need to apply some workarounds for gpu-specific vblank irq quirks * if flag is set. * @get_scanout_position: * Callback function to retrieve the scanout position. See * @struct drm_crtc_helper_funcs.get_scanout_position. * * Implements calculation of exact vblank timestamps from given drm_display_mode * timings and current video scanout position of a CRTC. * * The current implementation only handles standard video modes. For double scan * and interlaced modes the driver is supposed to adjust the hardware mode * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to * match the scanout position reported. * * Note that atomic drivers must call drm_calc_timestamping_constants() before * enabling a CRTC. The atomic helpers already take care of that in * drm_atomic_helper_calc_timestamping_constants(). * * Returns: * Returns true on success, and false on failure, i.e. when no accurate * timestamp could be acquired. */ bool drm_crtc_vblank_helper_get_vblank_timestamp_internal( struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time, bool in_vblank_irq, drm_vblank_get_scanout_position_func get_scanout_position) { struct drm_device *dev = crtc->dev; unsigned int pipe = crtc->index; struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; struct timespec64 ts_etime, ts_vblank_time; ktime_t stime, etime; bool vbl_status; const struct drm_display_mode *mode; int vpos, hpos, i; int delta_ns, duration_ns; if (pipe >= dev->num_crtcs) { drm_err(dev, "Invalid crtc %u\n", pipe); return false; } /* Scanout position query not supported? Should not happen. */ if (!get_scanout_position) { drm_err(dev, "Called from CRTC w/o get_scanout_position()!?\n"); return false; } if (drm_drv_uses_atomic_modeset(dev)) mode = &vblank->hwmode; else mode = &crtc->hwmode; /* If mode timing undefined, just return as no-op: * Happens during initial modesetting of a crtc. */ if (mode->crtc_clock == 0) { drm_dbg_core(dev, "crtc %u: Noop due to uninitialized mode.\n", pipe); drm_WARN_ON_ONCE(dev, drm_drv_uses_atomic_modeset(dev)); return false; } /* Get current scanout position with system timestamp. * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times * if single query takes longer than max_error nanoseconds. * * This guarantees a tight bound on maximum error if * code gets preempted or delayed for some reason. */ for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { /* * Get vertical and horizontal scanout position vpos, hpos, * and bounding timestamps stime, etime, pre/post query. */ vbl_status = get_scanout_position(crtc, in_vblank_irq, &vpos, &hpos, &stime, &etime, mode); /* Return as no-op if scanout query unsupported or failed. */ if (!vbl_status) { drm_dbg_core(dev, "crtc %u : scanoutpos query failed.\n", pipe); return false; } /* Compute uncertainty in timestamp of scanout position query. */ duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); /* Accept result with < max_error nsecs timing uncertainty. */ if (duration_ns <= *max_error) break; } /* Noisy system timing? */ if (i == DRM_TIMESTAMP_MAXRETRIES) { drm_dbg_core(dev, "crtc %u: Noisy timestamp %d us > %d us [%d reps].\n", pipe, duration_ns / 1000, *max_error / 1000, i); } /* Return upper bound of timestamp precision error. */ *max_error = duration_ns; /* Convert scanout position into elapsed time at raw_time query * since start of scanout at first display scanline. delta_ns * can be negative if start of scanout hasn't happened yet. */ delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), mode->crtc_clock); /* Subtract time delta from raw timestamp to get final * vblank_time timestamp for end of vblank. */ *vblank_time = ktime_sub_ns(etime, delta_ns); if (!drm_debug_enabled(DRM_UT_VBL)) return true; ts_etime = ktime_to_timespec64(etime); ts_vblank_time = ktime_to_timespec64(*vblank_time); drm_dbg_vbl(dev, "crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", pipe, hpos, vpos, (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, duration_ns / 1000, i); return true; } EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal); /** * drm_crtc_vblank_helper_get_vblank_timestamp - precise vblank timestamp * helper * @crtc: CRTC whose vblank timestamp to retrieve * @max_error: Desired maximum allowable error in timestamps (nanosecs) * On return contains true maximum error of timestamp * @vblank_time: Pointer to time which should receive the timestamp * @in_vblank_irq: * True when called from drm_crtc_handle_vblank(). Some drivers * need to apply some workarounds for gpu-specific vblank irq quirks * if flag is set. * * Implements calculation of exact vblank timestamps from given drm_display_mode * timings and current video scanout position of a CRTC. This can be directly * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms * driver if &drm_crtc_helper_funcs.get_scanout_position is implemented. * * The current implementation only handles standard video modes. For double scan * and interlaced modes the driver is supposed to adjust the hardware mode * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to * match the scanout position reported. * * Note that atomic drivers must call drm_calc_timestamping_constants() before * enabling a CRTC. The atomic helpers already take care of that in * drm_atomic_helper_calc_timestamping_constants(). * * Returns: * Returns true on success, and false on failure, i.e. when no accurate * timestamp could be acquired. */ bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time, bool in_vblank_irq) { return drm_crtc_vblank_helper_get_vblank_timestamp_internal( crtc, max_error, vblank_time, in_vblank_irq, crtc->helper_private->get_scanout_position); } EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp); /** * drm_crtc_get_last_vbltimestamp - retrieve raw timestamp for the most * recent vblank interval * @crtc: CRTC whose vblank timestamp to retrieve * @tvblank: Pointer to target time which should receive the timestamp * @in_vblank_irq: * True when called from drm_crtc_handle_vblank(). Some drivers * need to apply some workarounds for gpu-specific vblank irq quirks * if flag is set. * * Fetches the system timestamp corresponding to the time of the most recent * vblank interval on specified CRTC. May call into kms-driver to * compute the timestamp with a high-precision GPU specific method. * * Returns zero if timestamp originates from uncorrected do_gettimeofday() * call, i.e., it isn't very precisely locked to the true vblank. * * Returns: * True if timestamp is considered to be very precise, false otherwise. */ static bool drm_crtc_get_last_vbltimestamp(struct drm_crtc *crtc, ktime_t *tvblank, bool in_vblank_irq) { bool ret = false; /* Define requested maximum error on timestamps (nanoseconds). */ int max_error = (int) drm_timestamp_precision * 1000; /* Query driver if possible and precision timestamping enabled. */ if (crtc && crtc->funcs->get_vblank_timestamp && max_error > 0) { ret = crtc->funcs->get_vblank_timestamp(crtc, &max_error, tvblank, in_vblank_irq); } /* GPU high precision timestamp query unsupported or failed. * Return current monotonic/gettimeofday timestamp as best estimate. */ if (!ret) *tvblank = ktime_get(); return ret; } static bool drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe, ktime_t *tvblank, bool in_vblank_irq) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); return drm_crtc_get_last_vbltimestamp(crtc, tvblank, in_vblank_irq); } /** * drm_crtc_vblank_count - retrieve "cooked" vblank counter value * @crtc: which counter to retrieve * * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. Note that this timer isn't correct against a racing * vblank interrupt (since it only reports the software vblank counter), see * drm_crtc_accurate_vblank_count() for such use-cases. * * Note that for a given vblank counter value drm_crtc_handle_vblank() * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() * provide a barrier: Any writes done before calling * drm_crtc_handle_vblank() will be visible to callers of the later * functions, if the vblank count is the same or a later one. * * See also &drm_vblank_crtc.count. * * Returns: * The software vblank counter. */ u64 drm_crtc_vblank_count(struct drm_crtc *crtc) { return drm_vblank_count(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_count); /** * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the * system timestamp corresponding to that vblank counter value. * @dev: DRM device * @pipe: index of CRTC whose counter to retrieve * @vblanktime: Pointer to ktime_t to receive the vblank timestamp. * * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. Returns corresponding system timestamp of the time * of the vblank interval that corresponds to the current vblank counter value. * * This is the legacy version of drm_crtc_vblank_count_and_time(). */ static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe, ktime_t *vblanktime) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); u64 vblank_count; unsigned int seq; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) { *vblanktime = 0; return 0; } do { seq = read_seqbegin(&vblank->seqlock); vblank_count = atomic64_read(&vblank->count); *vblanktime = vblank->time; } while (read_seqretry(&vblank->seqlock, seq)); return vblank_count; } /** * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value * and the system timestamp corresponding to that vblank counter value * @crtc: which counter to retrieve * @vblanktime: Pointer to time to receive the vblank timestamp. * * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. Returns corresponding system timestamp of the time * of the vblank interval that corresponds to the current vblank counter value. * * Note that for a given vblank counter value drm_crtc_handle_vblank() * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() * provide a barrier: Any writes done before calling * drm_crtc_handle_vblank() will be visible to callers of the later * functions, if the vblank count is the same or a later one. * * See also &drm_vblank_crtc.count. */ u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, ktime_t *vblanktime) { return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc), vblanktime); } EXPORT_SYMBOL(drm_crtc_vblank_count_and_time); /** * drm_crtc_next_vblank_start - calculate the time of the next vblank * @crtc: the crtc for which to calculate next vblank time * @vblanktime: pointer to time to receive the next vblank timestamp. * * Calculate the expected time of the start of the next vblank period, * based on time of previous vblank and frame duration */ int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime) { struct drm_vblank_crtc *vblank; struct drm_display_mode *mode; u64 vblank_start; if (!drm_dev_has_vblank(crtc->dev)) return -EINVAL; vblank = drm_crtc_vblank_crtc(crtc); mode = &vblank->hwmode; if (!vblank->framedur_ns || !vblank->linedur_ns) return -EINVAL; if (!drm_crtc_get_last_vbltimestamp(crtc, vblanktime, false)) return -EINVAL; vblank_start = DIV_ROUND_DOWN_ULL( (u64)vblank->framedur_ns * mode->crtc_vblank_start, mode->crtc_vtotal); *vblanktime = ktime_add(*vblanktime, ns_to_ktime(vblank_start)); return 0; } EXPORT_SYMBOL(drm_crtc_next_vblank_start); static void send_vblank_event(struct drm_device *dev, struct drm_pending_vblank_event *e, u64 seq, ktime_t now) { struct timespec64 tv; switch (e->event.base.type) { case DRM_EVENT_VBLANK: case DRM_EVENT_FLIP_COMPLETE: tv = ktime_to_timespec64(now); e->event.vbl.sequence = seq; /* * e->event is a user space structure, with hardcoded unsigned * 32-bit seconds/microseconds. This is safe as we always use * monotonic timestamps since linux-4.15 */ e->event.vbl.tv_sec = tv.tv_sec; e->event.vbl.tv_usec = tv.tv_nsec / 1000; break; case DRM_EVENT_CRTC_SEQUENCE: if (seq) e->event.seq.sequence = seq; e->event.seq.time_ns = ktime_to_ns(now); break; } trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq); /* * Use the same timestamp for any associated fence signal to avoid * mismatch in timestamps for vsync & fence events triggered by the * same HW event. Frameworks like SurfaceFlinger in Android expects the * retire-fence timestamp to match exactly with HW vsync as it uses it * for its software vsync modeling. */ drm_send_event_timestamp_locked(dev, &e->base, now); } /** * drm_crtc_arm_vblank_event - arm vblank event after pageflip * @crtc: the source CRTC of the vblank event * @e: the event to send * * A lot of drivers need to generate vblank events for the very next vblank * interrupt. For example when the page flip interrupt happens when the page * flip gets armed, but not when it actually executes within the next vblank * period. This helper function implements exactly the required vblank arming * behaviour. * * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an * atomic commit must ensure that the next vblank happens at exactly the same * time as the atomic commit is committed to the hardware. This function itself * does **not** protect against the next vblank interrupt racing with either this * function call or the atomic commit operation. A possible sequence could be: * * 1. Driver commits new hardware state into vblank-synchronized registers. * 2. A vblank happens, committing the hardware state. Also the corresponding * vblank interrupt is fired off and fully processed by the interrupt * handler. * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event(). * 4. The event is only send out for the next vblank, which is wrong. * * An equivalent race can happen when the driver calls * drm_crtc_arm_vblank_event() before writing out the new hardware state. * * The only way to make this work safely is to prevent the vblank from firing * (and the hardware from committing anything else) until the entire atomic * commit sequence has run to completion. If the hardware does not have such a * feature (e.g. using a "go" bit), then it is unsafe to use this functions. * Instead drivers need to manually send out the event from their interrupt * handler by calling drm_crtc_send_vblank_event() and make sure that there's no * possible race with the hardware committing the atomic update. * * Caller must hold a vblank reference for the event @e acquired by a * drm_crtc_vblank_get(), which will be dropped when the next vblank arrives. */ void drm_crtc_arm_vblank_event(struct drm_crtc *crtc, struct drm_pending_vblank_event *e) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); assert_spin_locked(&dev->event_lock); e->pipe = pipe; e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1; list_add_tail(&e->base.link, &dev->vblank_event_list); } EXPORT_SYMBOL(drm_crtc_arm_vblank_event); /** * drm_crtc_send_vblank_event - helper to send vblank event after pageflip * @crtc: the source CRTC of the vblank event * @e: the event to send * * Updates sequence # and timestamp on event for the most recently processed * vblank, and sends it to userspace. Caller must hold event lock. * * See drm_crtc_arm_vblank_event() for a helper which can be used in certain * situation, especially to send out events for atomic commit operations. */ void drm_crtc_send_vblank_event(struct drm_crtc *crtc, struct drm_pending_vblank_event *e) { struct drm_device *dev = crtc->dev; u64 seq; unsigned int pipe = drm_crtc_index(crtc); ktime_t now; if (drm_dev_has_vblank(dev)) { seq = drm_vblank_count_and_time(dev, pipe, &now); } else { seq = 0; now = ktime_get(); } e->pipe = pipe; send_vblank_event(dev, e, seq, now); } EXPORT_SYMBOL(drm_crtc_send_vblank_event); static int __enable_vblank(struct drm_device *dev, unsigned int pipe) { if (drm_core_check_feature(dev, DRIVER_MODESET)) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); if (drm_WARN_ON(dev, !crtc)) return 0; if (crtc->funcs->enable_vblank) return crtc->funcs->enable_vblank(crtc); } return -EINVAL; } static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); int ret = 0; assert_spin_locked(&dev->vbl_lock); spin_lock(&dev->vblank_time_lock); if (!vblank->enabled) { /* * Enable vblank irqs under vblank_time_lock protection. * All vblank count & timestamp updates are held off * until we are done reinitializing master counter and * timestamps. Filtercode in drm_handle_vblank() will * prevent double-accounting of same vblank interval. */ ret = __enable_vblank(dev, pipe); drm_dbg_core(dev, "enabling vblank on crtc %u, ret: %d\n", pipe, ret); if (ret) { atomic_dec(&vblank->refcount); } else { drm_update_vblank_count(dev, pipe, 0); /* drm_update_vblank_count() includes a wmb so we just * need to ensure that the compiler emits the write * to mark the vblank as enabled after the call * to drm_update_vblank_count(). */ WRITE_ONCE(vblank->enabled, true); } } spin_unlock(&dev->vblank_time_lock); return ret; } int drm_vblank_get(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); unsigned long irqflags; int ret = 0; if (!drm_dev_has_vblank(dev)) return -EINVAL; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return -EINVAL; spin_lock_irqsave(&dev->vbl_lock, irqflags); /* Going from 0->1 means we have to enable interrupts again */ if (atomic_add_return(1, &vblank->refcount) == 1) { ret = drm_vblank_enable(dev, pipe); } else { if (!vblank->enabled) { atomic_dec(&vblank->refcount); ret = -EINVAL; } } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); return ret; } /** * drm_crtc_vblank_get - get a reference count on vblank events * @crtc: which CRTC to own * * Acquire a reference count on vblank events to avoid having them disabled * while in use. * * Returns: * Zero on success or a negative error code on failure. */ int drm_crtc_vblank_get(struct drm_crtc *crtc) { return drm_vblank_get(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_get); void drm_vblank_put(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); int vblank_offdelay = vblank->config.offdelay_ms; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; if (drm_WARN_ON(dev, atomic_read(&vblank->refcount) == 0)) return; /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&vblank->refcount)) { if (!vblank_offdelay) return; else if (vblank_offdelay < 0) vblank_disable_fn(vblank); else if (!vblank->config.disable_immediate) mod_timer(&vblank->disable_timer, jiffies + ((vblank_offdelay * HZ) / 1000)); } } /** * drm_crtc_vblank_put - give up ownership of vblank events * @crtc: which counter to give up * * Release ownership of a given vblank counter, turning off interrupts * if possible. Disable interrupts after &drm_vblank_crtc_config.offdelay_ms * milliseconds. */ void drm_crtc_vblank_put(struct drm_crtc *crtc) { drm_vblank_put(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_put); /** * drm_wait_one_vblank - wait for one vblank * @dev: DRM device * @pipe: CRTC index * * This waits for one vblank to pass on @pipe, using the irq driver interfaces. * It is a failure to call this when the vblank irq for @pipe is disabled, e.g. * due to lack of driver support or because the crtc is off. * * This is the legacy version of drm_crtc_wait_one_vblank(). */ void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); int ret; u64 last; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; #ifdef __OpenBSD__ /* * If we're cold, vblank interrupts won't happen even if * they're turned on by the driver. Just stall long enough * for a vblank to pass. This assumes a vrefresh of at least * 25 Hz. */ if (cold) { delay(40000); return; } #endif ret = drm_vblank_get(dev, pipe); if (drm_WARN(dev, ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret)) return; last = drm_vblank_count(dev, pipe); ret = wait_event_timeout(vblank->queue, last != drm_vblank_count(dev, pipe), msecs_to_jiffies(100)); drm_WARN(dev, ret == 0, "vblank wait timed out on crtc %i\n", pipe); drm_vblank_put(dev, pipe); } EXPORT_SYMBOL(drm_wait_one_vblank); /** * drm_crtc_wait_one_vblank - wait for one vblank * @crtc: DRM crtc * * This waits for one vblank to pass on @crtc, using the irq driver interfaces. * It is a failure to call this when the vblank irq for @crtc is disabled, e.g. * due to lack of driver support or because the crtc is off. */ void drm_crtc_wait_one_vblank(struct drm_crtc *crtc) { drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_wait_one_vblank); /** * drm_crtc_vblank_off - disable vblank events on a CRTC * @crtc: CRTC in question * * Drivers can use this function to shut down the vblank interrupt handling when * disabling a crtc. This function ensures that the latest vblank frame count is * stored so that drm_vblank_on can restore it again. * * Drivers must use this function when the hardware vblank counter can get * reset, e.g. when suspending or disabling the @crtc in general. */ void drm_crtc_vblank_off(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); struct drm_pending_vblank_event *e, *t; ktime_t now; u64 seq; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; /* * Grab event_lock early to prevent vblank work from being scheduled * while we're in the middle of shutting down vblank interrupts */ spin_lock_irq(&dev->event_lock); spin_lock(&dev->vbl_lock); drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n", pipe, vblank->enabled, vblank->inmodeset); /* Avoid redundant vblank disables without previous * drm_crtc_vblank_on(). */ if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset) drm_vblank_disable_and_save(dev, pipe); wake_up(&vblank->queue); /* * Prevent subsequent drm_vblank_get() from re-enabling * the vblank interrupt by bumping the refcount. */ if (!vblank->inmodeset) { atomic_inc(&vblank->refcount); vblank->inmodeset = 1; } spin_unlock(&dev->vbl_lock); /* Send any queued vblank events, lest the natives grow disquiet */ seq = drm_vblank_count_and_time(dev, pipe, &now); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != pipe) continue; drm_dbg_core(dev, "Sending premature vblank event on disable: " "wanted %llu, current %llu\n", e->sequence, seq); list_del(&e->base.link); drm_vblank_put(dev, pipe); send_vblank_event(dev, e, seq, now); } /* Cancel any leftover pending vblank work */ drm_vblank_cancel_pending_works(vblank); spin_unlock_irq(&dev->event_lock); /* Will be reset by the modeset helpers when re-enabling the crtc by * calling drm_calc_timestamping_constants(). */ vblank->hwmode.crtc_clock = 0; /* Wait for any vblank work that's still executing to finish */ drm_vblank_flush_worker(vblank); } EXPORT_SYMBOL(drm_crtc_vblank_off); /** * drm_crtc_vblank_reset - reset vblank state to off on a CRTC * @crtc: CRTC in question * * Drivers can use this function to reset the vblank state to off at load time. * Drivers should use this together with the drm_crtc_vblank_off() and * drm_crtc_vblank_on() functions. The difference compared to * drm_crtc_vblank_off() is that this function doesn't save the vblank counter * and hence doesn't need to call any driver hooks. * * This is useful for recovering driver state e.g. on driver load, or on resume. */ void drm_crtc_vblank_reset(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); spin_lock_irq(&dev->vbl_lock); /* * Prevent subsequent drm_vblank_get() from enabling the vblank * interrupt by bumping the refcount. */ if (!vblank->inmodeset) { atomic_inc(&vblank->refcount); vblank->inmodeset = 1; } spin_unlock_irq(&dev->vbl_lock); drm_WARN_ON(dev, !list_empty(&dev->vblank_event_list)); drm_WARN_ON(dev, !list_empty(&vblank->pending_work)); } EXPORT_SYMBOL(drm_crtc_vblank_reset); /** * drm_crtc_set_max_vblank_count - configure the hw max vblank counter value * @crtc: CRTC in question * @max_vblank_count: max hardware vblank counter value * * Update the maximum hardware vblank counter value for @crtc * at runtime. Useful for hardware where the operation of the * hardware vblank counter depends on the currently active * display configuration. * * For example, if the hardware vblank counter does not work * when a specific connector is active the maximum can be set * to zero. And when that specific connector isn't active the * maximum can again be set to the appropriate non-zero value. * * If used, must be called before drm_vblank_on(). */ void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, u32 max_vblank_count) { struct drm_device *dev = crtc->dev; struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); drm_WARN_ON(dev, dev->max_vblank_count); drm_WARN_ON(dev, !READ_ONCE(vblank->inmodeset)); vblank->max_vblank_count = max_vblank_count; } EXPORT_SYMBOL(drm_crtc_set_max_vblank_count); /** * drm_crtc_vblank_on_config - enable vblank events on a CRTC with custom * configuration options * @crtc: CRTC in question * @config: Vblank configuration value * * See drm_crtc_vblank_on(). In addition, this function allows you to provide a * custom vblank configuration for a given CRTC. * * Note that @config is copied, the pointer does not need to stay valid beyond * this function call. For details of the parameters see * struct drm_vblank_crtc_config. */ void drm_crtc_vblank_on_config(struct drm_crtc *crtc, const struct drm_vblank_crtc_config *config) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; spin_lock_irq(&dev->vbl_lock); drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n", pipe, vblank->enabled, vblank->inmodeset); vblank->config = *config; /* Drop our private "prevent drm_vblank_get" refcount */ if (vblank->inmodeset) { atomic_dec(&vblank->refcount); vblank->inmodeset = 0; } drm_reset_vblank_timestamp(dev, pipe); /* * re-enable interrupts if there are users left, or the * user wishes vblank interrupts to be enabled all the time. */ if (atomic_read(&vblank->refcount) != 0 || !vblank->config.offdelay_ms) drm_WARN_ON(dev, drm_vblank_enable(dev, pipe)); spin_unlock_irq(&dev->vbl_lock); } EXPORT_SYMBOL(drm_crtc_vblank_on_config); /** * drm_crtc_vblank_on - enable vblank events on a CRTC * @crtc: CRTC in question * * This functions restores the vblank interrupt state captured with * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be * unbalanced and so can also be unconditionally called in driver load code to * reflect the current hardware state of the crtc. * * Note that unlike in drm_crtc_vblank_on_config(), default values are used. */ void drm_crtc_vblank_on(struct drm_crtc *crtc) { const struct drm_vblank_crtc_config config = { .offdelay_ms = drm_vblank_offdelay, .disable_immediate = crtc->dev->vblank_disable_immediate }; drm_crtc_vblank_on_config(crtc, &config); } EXPORT_SYMBOL(drm_crtc_vblank_on); static void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) { ktime_t t_vblank; struct drm_vblank_crtc *vblank; int framedur_ns; u64 diff_ns; u32 cur_vblank, diff = 1; int count = DRM_TIMESTAMP_MAXRETRIES; u32 max_vblank_count = drm_max_vblank_count(dev, pipe); if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; assert_spin_locked(&dev->vbl_lock); assert_spin_locked(&dev->vblank_time_lock); vblank = drm_vblank_crtc(dev, pipe); drm_WARN_ONCE(dev, drm_debug_enabled(DRM_UT_VBL) && !vblank->framedur_ns, "Cannot compute missed vblanks without frame duration\n"); framedur_ns = vblank->framedur_ns; do { cur_vblank = __get_vblank_counter(dev, pipe); drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false); } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0); diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time)); if (framedur_ns) diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns); drm_dbg_vbl(dev, "missed %d vblanks in %lld ns, frame duration=%d ns, hw_diff=%d\n", diff, diff_ns, framedur_ns, cur_vblank - vblank->last); vblank->last = (cur_vblank - diff) & max_vblank_count; } /** * drm_crtc_vblank_restore - estimate missed vblanks and update vblank count. * @crtc: CRTC in question * * Power manamement features can cause frame counter resets between vblank * disable and enable. Drivers can use this function in their * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since * the last &drm_crtc_funcs.disable_vblank using timestamps and update the * vblank counter. * * Note that drivers must have race-free high-precision timestamping support, * i.e. &drm_crtc_funcs.get_vblank_timestamp must be hooked up and * &drm_vblank_crtc_config.disable_immediate must be set to indicate the * time-stamping functions are race-free against vblank hardware counter * increments. */ void drm_crtc_vblank_restore(struct drm_crtc *crtc) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); drm_WARN_ON_ONCE(dev, !crtc->funcs->get_vblank_timestamp); drm_WARN_ON_ONCE(dev, vblank->inmodeset); drm_WARN_ON_ONCE(dev, !vblank->config.disable_immediate); drm_vblank_restore(dev, pipe); } EXPORT_SYMBOL(drm_crtc_vblank_restore); static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe, u64 req_seq, union drm_wait_vblank *vblwait, struct drm_file *file_priv) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); struct drm_pending_vblank_event *e; ktime_t now; u64 seq; int ret; e = kzalloc(sizeof(*e), GFP_KERNEL); if (e == NULL) { ret = -ENOMEM; goto err_put; } e->pipe = pipe; e->event.base.type = DRM_EVENT_VBLANK; e->event.base.length = sizeof(e->event.vbl); e->event.vbl.user_data = vblwait->request.signal; e->event.vbl.crtc_id = 0; if (drm_core_check_feature(dev, DRIVER_MODESET)) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); if (crtc) e->event.vbl.crtc_id = crtc->base.id; } spin_lock_irq(&dev->event_lock); /* * drm_crtc_vblank_off() might have been called after we called * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the * vblank disable, so no need for further locking. The reference from * drm_vblank_get() protects against vblank disable from another source. */ if (!READ_ONCE(vblank->enabled)) { ret = -EINVAL; goto err_unlock; } ret = drm_event_reserve_init_locked(dev, file_priv, &e->base, &e->event.base); if (ret) goto err_unlock; seq = drm_vblank_count_and_time(dev, pipe, &now); drm_dbg_core(dev, "event on vblank count %llu, current %llu, crtc %u\n", req_seq, seq, pipe); trace_drm_vblank_event_queued(file_priv, pipe, req_seq); e->sequence = req_seq; if (drm_vblank_passed(seq, req_seq)) { drm_vblank_put(dev, pipe); send_vblank_event(dev, e, seq, now); vblwait->reply.sequence = seq; } else { /* drm_handle_vblank_events will call drm_vblank_put */ list_add_tail(&e->base.link, &dev->vblank_event_list); vblwait->reply.sequence = req_seq; } spin_unlock_irq(&dev->event_lock); return 0; err_unlock: spin_unlock_irq(&dev->event_lock); kfree(e); err_put: drm_vblank_put(dev, pipe); return ret; } static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait) { if (vblwait->request.sequence) return false; return _DRM_VBLANK_RELATIVE == (vblwait->request.type & (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_EVENT | _DRM_VBLANK_NEXTONMISS)); } /* * Widen a 32-bit param to 64-bits. * * \param narrow 32-bit value (missing upper 32 bits) * \param near 64-bit value that should be 'close' to near * * This function returns a 64-bit value using the lower 32-bits from * 'narrow' and constructing the upper 32-bits so that the result is * as close as possible to 'near'. */ static u64 widen_32_to_64(u32 narrow, u64 near) { return near + (s32) (narrow - near); } static void drm_wait_vblank_reply(struct drm_device *dev, unsigned int pipe, struct drm_wait_vblank_reply *reply) { ktime_t now; struct timespec64 ts; /* * drm_wait_vblank_reply is a UAPI structure that uses 'long' * to store the seconds. This is safe as we always use monotonic * timestamps since linux-4.15. */ reply->sequence = drm_vblank_count_and_time(dev, pipe, &now); ts = ktime_to_timespec64(now); reply->tval_sec = (u32)ts.tv_sec; reply->tval_usec = ts.tv_nsec / 1000; } static bool drm_wait_vblank_supported(struct drm_device *dev) { return drm_dev_has_vblank(dev); } int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_crtc *crtc; struct drm_vblank_crtc *vblank; union drm_wait_vblank *vblwait = data; int ret; u64 req_seq, seq; unsigned int pipe_index; unsigned int flags, pipe, high_pipe; if (!drm_wait_vblank_supported(dev)) return -EOPNOTSUPP; if (vblwait->request.type & _DRM_VBLANK_SIGNAL) return -EINVAL; if (vblwait->request.type & ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | _DRM_VBLANK_HIGH_CRTC_MASK)) { drm_dbg_core(dev, "Unsupported type value 0x%x, supported mask 0x%x\n", vblwait->request.type, (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | _DRM_VBLANK_HIGH_CRTC_MASK)); return -EINVAL; } flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK); if (high_pipe) pipe_index = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT; else pipe_index = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; /* Convert lease-relative crtc index into global crtc index */ if (drm_core_check_feature(dev, DRIVER_MODESET)) { pipe = 0; drm_for_each_crtc(crtc, dev) { if (drm_lease_held(file_priv, crtc->base.id)) { if (pipe_index == 0) break; pipe_index--; } pipe++; } } else { pipe = pipe_index; } if (pipe >= dev->num_crtcs) return -EINVAL; vblank = &dev->vblank[pipe]; /* If the counter is currently enabled and accurate, short-circuit * queries to return the cached timestamp of the last vblank. */ if (vblank->config.disable_immediate && drm_wait_vblank_is_query(vblwait) && READ_ONCE(vblank->enabled)) { drm_wait_vblank_reply(dev, pipe, &vblwait->reply); return 0; } ret = drm_vblank_get(dev, pipe); if (ret) { drm_dbg_core(dev, "crtc %d failed to acquire vblank counter, %d\n", pipe, ret); return ret; } seq = drm_vblank_count(dev, pipe); switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { case _DRM_VBLANK_RELATIVE: req_seq = seq + vblwait->request.sequence; vblwait->request.sequence = req_seq; vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; break; case _DRM_VBLANK_ABSOLUTE: req_seq = widen_32_to_64(vblwait->request.sequence, seq); break; default: ret = -EINVAL; goto done; } if ((flags & _DRM_VBLANK_NEXTONMISS) && drm_vblank_passed(seq, req_seq)) { req_seq = seq + 1; vblwait->request.type &= ~_DRM_VBLANK_NEXTONMISS; vblwait->request.sequence = req_seq; } if (flags & _DRM_VBLANK_EVENT) { /* must hold on to the vblank ref until the event fires * drm_vblank_put will be called asynchronously */ return drm_queue_vblank_event(dev, pipe, req_seq, vblwait, file_priv); } if (req_seq != seq) { int wait; drm_dbg_core(dev, "waiting on vblank count %llu, crtc %u\n", req_seq, pipe); wait = wait_event_interruptible_timeout(vblank->queue, drm_vblank_passed(drm_vblank_count(dev, pipe), req_seq) || !READ_ONCE(vblank->enabled), msecs_to_jiffies(3000)); switch (wait) { case 0: /* timeout */ ret = -EBUSY; break; case -ERESTARTSYS: /* interrupted by signal */ ret = -EINTR; break; default: ret = 0; break; } } if (ret != -EINTR) { drm_wait_vblank_reply(dev, pipe, &vblwait->reply); drm_dbg_core(dev, "crtc %d returning %u to client\n", pipe, vblwait->reply.sequence); } else { drm_dbg_core(dev, "crtc %d vblank wait interrupted by signal\n", pipe); } done: drm_vblank_put(dev, pipe); return ret; } static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe) { struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); bool high_prec = false; struct drm_pending_vblank_event *e, *t; ktime_t now; u64 seq; assert_spin_locked(&dev->event_lock); seq = drm_vblank_count_and_time(dev, pipe, &now); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != pipe) continue; if (!drm_vblank_passed(seq, e->sequence)) continue; drm_dbg_core(dev, "vblank event on %llu, current %llu\n", e->sequence, seq); list_del(&e->base.link); drm_vblank_put(dev, pipe); send_vblank_event(dev, e, seq, now); } if (crtc && crtc->funcs->get_vblank_timestamp) high_prec = true; trace_drm_vblank_event(pipe, seq, now, high_prec); } /** * drm_handle_vblank - handle a vblank event * @dev: DRM device * @pipe: index of CRTC where this event occurred * * Drivers should call this routine in their vblank interrupt handlers to * update the vblank counter and send any signals that may be pending. * * This is the legacy version of drm_crtc_handle_vblank(). */ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); unsigned long irqflags; bool disable_irq; if (drm_WARN_ON_ONCE(dev, !drm_dev_has_vblank(dev))) return false; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return false; spin_lock_irqsave(&dev->event_lock, irqflags); /* Need timestamp lock to prevent concurrent execution with * vblank enable/disable, as this would cause inconsistent * or corrupted timestamps and vblank counts. */ spin_lock(&dev->vblank_time_lock); /* Vblank irq handling disabled. Nothing to do. */ if (!vblank->enabled) { spin_unlock(&dev->vblank_time_lock); spin_unlock_irqrestore(&dev->event_lock, irqflags); return false; } drm_update_vblank_count(dev, pipe, true); spin_unlock(&dev->vblank_time_lock); wake_up(&vblank->queue); /* With instant-off, we defer disabling the interrupt until after * we finish processing the following vblank after all events have * been signaled. The disable has to be last (after * drm_handle_vblank_events) so that the timestamp is always accurate. */ disable_irq = (vblank->config.disable_immediate && vblank->config.offdelay_ms > 0 && !atomic_read(&vblank->refcount)); drm_handle_vblank_events(dev, pipe); drm_handle_vblank_works(vblank); spin_unlock_irqrestore(&dev->event_lock, irqflags); if (disable_irq) vblank_disable_fn(vblank); return true; } EXPORT_SYMBOL(drm_handle_vblank); /** * drm_crtc_handle_vblank - handle a vblank event * @crtc: where this event occurred * * Drivers should call this routine in their vblank interrupt handlers to * update the vblank counter and send any signals that may be pending. * * This is the native KMS version of drm_handle_vblank(). * * Note that for a given vblank counter value drm_crtc_handle_vblank() * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() * provide a barrier: Any writes done before calling * drm_crtc_handle_vblank() will be visible to callers of the later * functions, if the vblank count is the same or a later one. * * See also &drm_vblank_crtc.count. * * Returns: * True if the event was successfully handled, false on failure. */ bool drm_crtc_handle_vblank(struct drm_crtc *crtc) { return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_handle_vblank); /* * Get crtc VBLANK count. * * \param dev DRM device * \param data user argument, pointing to a drm_crtc_get_sequence structure. * \param file_priv drm file private for the user's open file descriptor */ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_crtc *crtc; struct drm_vblank_crtc *vblank; int pipe; struct drm_crtc_get_sequence *get_seq = data; ktime_t now; bool vblank_enabled; int ret; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; if (!drm_dev_has_vblank(dev)) return -EOPNOTSUPP; crtc = drm_crtc_find(dev, file_priv, get_seq->crtc_id); if (!crtc) return -ENOENT; pipe = drm_crtc_index(crtc); vblank = drm_crtc_vblank_crtc(crtc); vblank_enabled = READ_ONCE(vblank->config.disable_immediate) && READ_ONCE(vblank->enabled); if (!vblank_enabled) { ret = drm_crtc_vblank_get(crtc); if (ret) { drm_dbg_core(dev, "crtc %d failed to acquire vblank counter, %d\n", pipe, ret); return ret; } } drm_modeset_lock(&crtc->mutex, NULL); if (crtc->state) get_seq->active = crtc->state->enable; else get_seq->active = crtc->enabled; drm_modeset_unlock(&crtc->mutex); get_seq->sequence = drm_vblank_count_and_time(dev, pipe, &now); get_seq->sequence_ns = ktime_to_ns(now); if (!vblank_enabled) drm_crtc_vblank_put(crtc); return 0; } /* * Queue a event for VBLANK sequence * * \param dev DRM device * \param data user argument, pointing to a drm_crtc_queue_sequence structure. * \param file_priv drm file private for the user's open file descriptor */ int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_crtc *crtc; struct drm_vblank_crtc *vblank; int pipe; struct drm_crtc_queue_sequence *queue_seq = data; ktime_t now; struct drm_pending_vblank_event *e; u32 flags; u64 seq; u64 req_seq; int ret; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; if (!drm_dev_has_vblank(dev)) return -EOPNOTSUPP; crtc = drm_crtc_find(dev, file_priv, queue_seq->crtc_id); if (!crtc) return -ENOENT; flags = queue_seq->flags; /* Check valid flag bits */ if (flags & ~(DRM_CRTC_SEQUENCE_RELATIVE| DRM_CRTC_SEQUENCE_NEXT_ON_MISS)) return -EINVAL; pipe = drm_crtc_index(crtc); vblank = drm_crtc_vblank_crtc(crtc); e = kzalloc(sizeof(*e), GFP_KERNEL); if (e == NULL) return -ENOMEM; ret = drm_crtc_vblank_get(crtc); if (ret) { drm_dbg_core(dev, "crtc %d failed to acquire vblank counter, %d\n", pipe, ret); goto err_free; } seq = drm_vblank_count_and_time(dev, pipe, &now); req_seq = queue_seq->sequence; if (flags & DRM_CRTC_SEQUENCE_RELATIVE) req_seq += seq; if ((flags & DRM_CRTC_SEQUENCE_NEXT_ON_MISS) && drm_vblank_passed(seq, req_seq)) req_seq = seq + 1; e->pipe = pipe; e->event.base.type = DRM_EVENT_CRTC_SEQUENCE; e->event.base.length = sizeof(e->event.seq); e->event.seq.user_data = queue_seq->user_data; spin_lock_irq(&dev->event_lock); /* * drm_crtc_vblank_off() might have been called after we called * drm_crtc_vblank_get(). drm_crtc_vblank_off() holds event_lock around the * vblank disable, so no need for further locking. The reference from * drm_crtc_vblank_get() protects against vblank disable from another source. */ if (!READ_ONCE(vblank->enabled)) { ret = -EINVAL; goto err_unlock; } ret = drm_event_reserve_init_locked(dev, file_priv, &e->base, &e->event.base); if (ret) goto err_unlock; e->sequence = req_seq; if (drm_vblank_passed(seq, req_seq)) { drm_crtc_vblank_put(crtc); send_vblank_event(dev, e, seq, now); queue_seq->sequence = seq; } else { /* drm_handle_vblank_events will call drm_vblank_put */ list_add_tail(&e->base.link, &dev->vblank_event_list); queue_seq->sequence = req_seq; } spin_unlock_irq(&dev->event_lock); return 0; err_unlock: spin_unlock_irq(&dev->event_lock); drm_crtc_vblank_put(crtc); err_free: kfree(e); return ret; }
