/*
        Copyright 1999, Be Incorporated.   All Rights Reserved.
        This file may be used under the terms of the Be Sample Code License.

        Other authors for NV driver:
        Mark Watson,
        Rudolf Cornelissen 9/2002-1/2016
*/

#define MODULE_BIT 0x00400000

#include "acc_std.h"

#define T_POSITIVE_SYNC (B_POSITIVE_HSYNC | B_POSITIVE_VSYNC)
/* mode flags will be setup as status info by PROPOSEMODE! */
#define MODE_FLAGS 0
#define MODE_COUNT (sizeof (mode_list) / sizeof (display_mode))

/* Standard VESA modes,
 * plus panel specific resolution modes which are internally modified during run-time depending on the requirements of the actual
 * panel connected. The modes as listed here, should timing-wise be as compatible with analog (CRT) monitors as can be... */
//fixme: if EDID monitor found create list via common EDID code...
static const display_mode mode_list[] = {
/* 4:3 modes; 307.2k pixels */
{ { 25175, 640, 656, 752, 800, 480, 490, 492, 525, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(640X480X8.Z1) */
{ { 27500, 640, 672, 768, 864, 480, 488, 494, 530, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* 640X480X60Hz */
{ { 30500, 640, 672, 768, 864, 480, 517, 523, 588, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* SVGA_640X480X60HzNI */
{ { 31500, 640, 664, 704, 832, 480, 489, 492, 520, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70-72Hz_(640X480X8.Z1) */
{ { 31500, 640, 656, 720, 840, 480, 481, 484, 500, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(640X480X8.Z1) */
{ { 36000, 640, 696, 752, 832, 480, 481, 484, 509, 0}, B_CMAP8, 640, 480, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@85Hz_(640X480X8.Z1) */
/* 4:3 modes; 480k pixels */
{ { 36000, 800, 824, 896, 1024, 600, 601, 603, 625, 0}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@56Hz_(800X600) from Be, Inc. driver + XFree86 */
{ { 38100, 800, 832, 960, 1088, 600, 602, 606, 620, 0}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* SVGA_800X600X56HzNI */
{ { 40000, 800, 840, 968, 1056, 600, 601, 605, 628, T_POSITIVE_SYNC}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(800X600X8.Z1) + XFree86 */
{ { 49500, 800, 816, 896, 1056, 600, 601, 604, 625, T_POSITIVE_SYNC}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(800X600X8.Z1) + XFree86 */
{ { 50000, 800, 856, 976, 1040, 600, 637, 643, 666, T_POSITIVE_SYNC}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70-72Hz_(800X600X8.Z1) + XFree86 */
{ { 56250, 800, 832, 896, 1048, 600, 601, 604, 631, T_POSITIVE_SYNC}, B_CMAP8, 800, 600, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@85Hz_(800X600X8.Z1) + XFree86 */
/* 4:3 modes; 786.432k pixels */
{ { 65000, 1024, 1048, 1184, 1344, 768, 771, 777, 806, 0}, B_CMAP8, 1024, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1024X768X8.Z1) + XFree86 */
{ { 75000, 1024, 1048, 1184, 1328, 768, 771, 777, 806, 0}, B_CMAP8, 1024, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70-72Hz_(1024X768X8.Z1) + XFree86 */
{ { 78750, 1024, 1040, 1136, 1312, 768, 769, 772, 800, T_POSITIVE_SYNC}, B_CMAP8, 1024, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1024X768X8.Z1) + XFree86 */
{ { 94500, 1024, 1072, 1168, 1376, 768, 769, 772, 808, T_POSITIVE_SYNC}, B_CMAP8, 1024, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@85Hz_(1024X768X8.Z1) + XFree86 */
/* 4:3 modes; 995.328k pixels */
{ { 94200, 1152, 1184, 1280, 1472, 864, 865, 868, 914, T_POSITIVE_SYNC}, B_CMAP8, 1152, 864, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70Hz_(1152X864X8.Z1) */
{ { 97800, 1152, 1216, 1344, 1552, 864, 865, 868, 900, T_POSITIVE_SYNC}, B_CMAP8, 1152, 864, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70Hz_(1152X864X8.Z1) */
{ { 108000, 1152, 1216, 1344, 1600, 864, 865, 868, 900, T_POSITIVE_SYNC}, B_CMAP8, 1152, 864, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1152X864X8.Z1) + XFree86 */
{ { 121500, 1152, 1216, 1344, 1568, 864, 865, 868, 911, T_POSITIVE_SYNC}, B_CMAP8, 1152, 864, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@85Hz_(1152X864X8.Z1) */
/* 5:4 modes; 1.311M pixels */
{ { 108000, 1280, 1328, 1440, 1688, 1024, 1025, 1028, 1066, T_POSITIVE_SYNC}, B_CMAP8, 1280, 1024, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1280X1024) from Be, Inc. driver + XFree86 */
{ { 135000, 1280, 1296, 1440, 1688, 1024, 1025, 1028, 1066, T_POSITIVE_SYNC}, B_CMAP8, 1280, 1024, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1280X1024X8.Z1) + XFree86 */
{ { 157500, 1280, 1344, 1504, 1728, 1024, 1025, 1028, 1072, T_POSITIVE_SYNC}, B_CMAP8, 1280, 1024, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@85Hz_(1280X1024X8.Z1) + XFree86 */
/* 4:3 panel mode; 1.47M pixels */
{ { 122600, 1400, 1488, 1640, 1880, 1050, 1051, 1054, 1087, T_POSITIVE_SYNC}, B_CMAP8, 1400, 1050, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1400X1050) */
/* 4:3 modes; 1.92M pixels */
{ { 162000, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1600X1200X8.Z1) + XFree86 */
/* identical lines to above one, apart from refreshrate.. */
{ { 175500, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@65Hz_(1600X1200X8.Z1) + XFree86 */
{ { 189000, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@70Hz_(1600X1200X8.Z1) + XFree86 */
{ { 202500, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1600X1200X8.Z1) + XFree86 */
{ { 216000, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@80Hz_(1600X1200X8.Z1) */
{ { 229500, 1600, 1664, 1856, 2160, 1200, 1201, 1204, 1250, T_POSITIVE_SYNC}, B_CMAP8, 1600, 1200, 0, 0, MODE_FLAGS},  /* Vesa_Monitor_@85Hz_(1600X1200X8.Z1) + XFree86 */
/* end identical lines. */
/* 4:3 modes; 2.408M pixels */
{ { 204750, 1792, 1920, 2120, 2448, 1344, 1345, 1348, 1394, B_POSITIVE_VSYNC}, B_CMAP8, 1792, 1344, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1792X1344) from Be, Inc. driver + XFree86 */
{ { 261000, 1792, 1888, 2104, 2456, 1344, 1345, 1348, 1417, B_POSITIVE_VSYNC}, B_CMAP8, 1792, 1344, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1792X1344) from Be, Inc. driver + XFree86 */
/* 4:3 modes; 2.584M pixels */
{ { 218250, 1856, 1952, 2176, 2528, 1392, 1393, 1396, 1439, B_POSITIVE_VSYNC}, B_CMAP8, 1856, 1392, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1856X1392) from Be, Inc. driver + XFree86 */
{ { 288000, 1856, 1984, 2208, 2560, 1392, 1393, 1396, 1500, B_POSITIVE_VSYNC}, B_CMAP8, 1856, 1392, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1856X1392) from Be, Inc. driver + XFree86 */
/* 4:3 modes; 2.765M pixels */
{ { 234000, 1920, 2048, 2256, 2600, 1440, 1441, 1444, 1500, B_POSITIVE_VSYNC}, B_CMAP8, 1920, 1440, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1920X1440) from Be, Inc. driver + XFree86 */
{ { 297000, 1920, 2064, 2288, 2640, 1440, 1441, 1444, 1500, B_POSITIVE_VSYNC}, B_CMAP8, 1920, 1440, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@75Hz_(1920X1440) from Be, Inc. driver + XFree86 */
/* 4:3 modes; 3.146M pixels */
{ { 266950, 2048, 2200, 2424, 2800, 1536, 1537, 1540, 1589, B_POSITIVE_VSYNC}, B_CMAP8, 2048, 1536, 0, 0, MODE_FLAGS}, /* From XFree86 posting @60Hz + XFree86 */
/* 16:10 panel mode; 400k pixels */
{ { 31300, 800, 848, 928, 1008, 500, 501, 504, 518, T_POSITIVE_SYNC}, B_CMAP8, 800, 500, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(800X500) */
/* 16:10 panel mode; 655.36k pixels */
{ { 52800, 1024, 1072, 1176, 1328, 640, 641, 644, 663, T_POSITIVE_SYNC}, B_CMAP8, 1024, 640, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1024X640) */
/* 16:10 panel-TV mode; 983.04k pixels */
{ { 80135, 1280, 1344, 1480, 1680, 768, 769, 772, 795, T_POSITIVE_SYNC}, B_CMAP8, 1280, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1280X768) */
/* 16:10 panel mode; 1.024M pixels */
{ { 83500, 1280, 1344, 1480, 1680, 800, 801, 804, 828, T_POSITIVE_SYNC}, B_CMAP8, 1280, 800, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1280X800) */
/* 16:10 panel mode; 1.296M pixels */
{ { 106500, 1440, 1520, 1672, 1904, 900, 901, 904, 932, T_POSITIVE_SYNC}, B_CMAP8, 1440, 900, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1440X900) */
/* 16:10 panel mode; 1.764M pixels */
{ { 147100, 1680, 1784, 1968, 2256, 1050, 1051, 1054, 1087, T_POSITIVE_SYNC}, B_CMAP8, 1680, 1050, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1680X1050) */
/* 16:10 panel mode; 2.304M pixels */
{ { 193160, 1920, 2048, 2256, 2592, 1200, 1201, 1204, 1242, T_POSITIVE_SYNC}, B_CMAP8, 1920, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1920X1200) */
//{ { 160000, 1920, 2010, 2060, 2110, 1200, 1202, 1208, 1235, T_POSITIVE_SYNC}, B_CMAP8, 1920, 1200, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1920X1200) */
/* 16:9 panel mode; 1280x720 (HDTV 1280x720p) */
{ { 74520, 1280, 1368, 1424, 1656, 720, 724, 730, 750, T_POSITIVE_SYNC}, B_CMAP8, 1280, 720, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1280X720) */
/* 16:9 panel mode; 1366x768 (HDTV '1280x720p')
   note: horizontal CRTC timing must be a multiple of 8! (hardware restriction) */
{ { 85500, 1368, 1440, 1576, 1792, 768, 771, 774, 798, T_POSITIVE_SYNC}, B_CMAP8, 1368, 768, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1366X768) */
/* 16:9 panel mode; 1920x1080 (HDTV 1920x1080p) */
{ { 148500, 1920, 2008, 2052, 2200, 1080, 1084, 1089, 1125, T_POSITIVE_SYNC}, B_CMAP8, 1920, 1080, 0, 0, MODE_FLAGS}, /* Vesa_Monitor_@60Hz_(1920X1080) */
};


// transform official mode to internal, multi-screen mode enhanced mode
static void Haiku_DetectTranslateMultiMode(display_mode *mode)
{
        mode->flags &= ~DUALHEAD_BITS;

        if( mode->virtual_width == 2 * mode->timing.h_display ) {
                LOG(4, ("Haiku: horizontal combine mode\n"));
                if (si->Haiku_switch_head)
                        mode->flags |= DUALHEAD_SWITCH;
                else
                        mode->flags |= DUALHEAD_ON;
        } else if( mode->virtual_height == 2 * mode->timing.v_display ) {
                LOG(4, ("Haiku: vertical combine mode not supported\n"));
        } else {
                /* unfortunately Haiku's screenprefs panel does not support single head output explicitly, so we'd better
                   activate both heads always to (probably) mimic Radeon driver behaviour (for which this app was adapted) */
                /* note please:
                   - this will have a big downside on hardware for which both heads have different resolution cababilities (i.e. Matrox);
                   - also (on laptops) this will shorten battery life a bit of course.. */
                mode->flags |= DUALHEAD_CLONE;
        }
}


// check and execute tunnel settings command
static status_t Haiku_CheckMultiMonTunnel(display_mode *mode, const display_mode *low, const display_mode *high, bool *isTunneled )
{
        if( (mode->timing.flags & RADEON_MODE_MULTIMON_REQUEST) != 0 &&
                (mode->timing.flags & RADEON_MODE_MULTIMON_REPLY) == 0 )
        {
                mode->timing.flags &= ~RADEON_MODE_MULTIMON_REQUEST;
                mode->timing.flags |= RADEON_MODE_MULTIMON_REPLY;
                
                // still process request, just in case someone set this flag
                // combination by mistake
                
                *isTunneled = true;
                return B_OK;
        }

        // check magic params
        if( mode->space != 0 || low->space != 0 || high->space != 0 
                || low->virtual_width != 0xffff || low->virtual_height != 0xffff
                || high->virtual_width != 0 || high->virtual_height != 0
                || mode->timing.pixel_clock != 0 
                || low->timing.pixel_clock != 'TKTK' || high->timing.pixel_clock != 'KTKT' )
        {
                *isTunneled = false;
                return B_OK;
        }

        *isTunneled = true;

        /* enable Haiku special handling */
        if (!si->haiku_prefs_used)
                LOG(4, ("PROPOSEMODE: Haiku screenprefs tunnel detected.\n"));
        si->haiku_prefs_used = true;

        /* note please:
           Haiku ScreenPrefs does not issue a SetMode command after changing these settings (per se), but relies on
           driver switching outputs directly. These settings are not dependant on workspace there, and are not part of 
           the mode in the Radeon driver. In the Matrox and nVidia drivers they are though. So we need SetMode
           to be issued. (yes: sometimes I switch monitors when I switch workspace.. ;-)
           Also the RADEON driver saves these settings to a file so it remembers these after reboots. We don't atm.
           If the mode as proposed by the driver would be saved by the ScreenPrefs panel, we would 'remember' it over
           reboots though (via app_server settings).. */

        switch( mode->h_display_start ) {
        case ms_swap:
                switch( mode->v_display_start ) {
                case 0:
                        if (si->Haiku_switch_head)
                                mode->timing.flags = 1;
                        else
                                mode->timing.flags = 0;
                        LOG(4, ("Haiku: tunnel access target=swap, command=get, value=%u\n", mode->timing.flags));
                        return B_OK;
                case 1:
                        si->Haiku_switch_head = mode->timing.flags != 0;
                        LOG(4, ("Haiku: tunnel access target=swap, command=set, value=%u\n", mode->timing.flags));
                        /* Haiku's screenprefs panel expects us to directly set the mode.. (but it should do that itself) */
                        SET_DISPLAY_MODE(&si->dm);
                        return B_OK;
                }
                break;

        case ms_use_laptop_panel:
                LOG(4, ("Haiku: tunnel access target=usepanel, command=%s, value=%u\n",
                        (mode->v_display_start == 1) ? "set" : "get", mode->timing.flags));
                // we refuse this setting (makes no sense for us: laptop panel is treated as normal screen)
                return B_ERROR;
                break;

        case ms_tv_standard:
                LOG(4, ("Haiku: tunnel access target=tvstandard, command=%s, value=%u\n",
                        (mode->v_display_start == 1) ? "set" : "get", mode->timing.flags));
                // let's forget about this for now..
                return B_ERROR;
                break;
        }

        LOG(4, ("Haiku: unhandled tunnel access target=$%x, command=%u, value=%u\n",
                mode->h_display_start, mode->v_display_start, mode->timing.flags));

        return B_ERROR;
}


/*!
        Check mode is between low and high limits.
        Returns:
        B_OK - found one
        B_BAD_VALUE - mode can be made, but outside limits
        B_ERROR - not possible
*/
/* BOUNDS WARNING:
 * BeOS (tested R5.0.3PE) is failing BWindowScreen.SetFrameBuffer() if PROPOSEMODE
 * returns B_BAD_VALUE. It's called by the OS with target, low and high set to
 * have the same settings for BWindowScreen!
 * Which means we should not return B_BAD_VALUE on anything except for deviations on:
 * display_mode.virtual_width;
 * display_mode.virtual_height;
 * display_mode.timing.h_display;
 * display_mode.timing.v_display;
 */
/* Note:
 * The target mode should be modified to correspond to the mode as it can be made. */
status_t
PROPOSE_DISPLAY_MODE(display_mode *target, const display_mode *low, const display_mode *high) 
{
        status_t status = B_OK;
        float pix_clock_found, target_aspect;
        uint8 m,n,p, bpp;
        status_t result;
        uint32 max_vclk, row_bytes, mem_reservation;
        bool acc_mode;
        double target_refresh = ((double)target->timing.pixel_clock * 1000.0)
                / ((double)target->timing.h_total * (double)target->timing.v_total);
        bool want_same_width = target->timing.h_display == target->virtual_width;
        bool want_same_height = target->timing.v_display == target->virtual_height;
        bool isTunneled = false;
        // check whether we got a tunneled settings command
        result = Haiku_CheckMultiMonTunnel(target, low, high, &isTunneled);
        if (isTunneled)
                return result;

        /* since we (might be) called by the Haiku ScreenPrefs panel, check for special modes and translate
           them from (for us) non-native modes to native modes (as used in DualheadSetup by Mark Watson).
           These 'native modes' survive system reboots by the way, at least when set using DualheadSetup. */

        /* note please: apparantly Haiku Screenprefs does not save the modes as set by the driver, but as originally requested
           by the ScreenPrefs panel. Modifications done by the driver are therefore not saved.
           It would be nice if the screenprefs panel in Haiku would save the modified modeflags (after proposemode or setmode),
           that would also make the driver remember switched heads (now it's a temporary setting). */

        if (si->haiku_prefs_used) {
                // check how many heads are needed by target mode
                Haiku_DetectTranslateMultiMode(target);
        }

        LOG(1, ("PROPOSEMODE: (ENTER) requested virtual_width %d, virtual_height %d\n",
                target->virtual_width, target->virtual_height));

        /*find a nearby valid timing from that given*/
        result = head1_validate_timing(&target->timing.h_display,
                &target->timing.h_sync_start, &target->timing.h_sync_end,
                &target->timing.h_total, &target->timing.v_display,
                &target->timing.v_sync_start, &target->timing.v_sync_end,
                &target->timing.v_total);
        if (result == B_ERROR) {
                LOG(4, ("PROPOSEMODE: could not validate timing, aborted.\n"));
                return result;
        }

        /* disable aspect checks for a requested TVout mode when mode is TVout capable */
        if (!si->ps.tvout
                || !(BT_check_tvmode(*target) && (target->flags & TV_BITS))) {
                /* check if all connected output devices can display the requested mode's aspect.
                 * assuming 16:10 screens can display non-WS modes, but cannot (correctly) display 16:9 modes;
                 * assuming  16:9 screens can display non-WS modes, and can display 16:10 modes. */
                /* calculate display mode aspect */
                target_aspect = (target->timing.h_display / ((float)target->timing.v_display));
                /* NOTE:
                 * allow 0.10 difference so 5:4 aspect panels will be able to use 4:3 aspect modes! */
                switch (si->ps.monitors) {
                        case 0: /* no monitor found at all */
                                /* if forcing widescreen type was requested don't block mode */
                                if (target_aspect > 1.34 && !si->settings.force_ws) {
                                        LOG(4, ("PROPOSEMODE: not all output devices can display widescreen modes, aborted.\n"));
                                        return B_ERROR;
                                }
                                break;
                        case CRTC1_TMDS:        /* digital panel on head 1, nothing on head 2 */
                        case CRTC1_VGA:         /* analog connected screen on head 1, nothing on head 2 */
                                if (si->ps.crtc1_screen.aspect < (target_aspect - 0.10)) {
                                        LOG(4, ("PROPOSEMODE: screen at crtc1 is not widescreen (enough) type, aborted.\n"));
                                        return B_ERROR;
                                }
                                break;
                        case CRTC2_TMDS:        /* nothing on head 1, digital panel on head 2 */
                        case CRTC2_VGA:         /* analog connected screen on head 2, nothing on head 1 */
                                if (si->ps.crtc2_screen.aspect < (target_aspect - 0.10)) {
                                        LOG(4, ("PROPOSEMODE: screen at crtc2 is not widescreen (enough) type, aborted.\n"));
                                        return B_ERROR;
                                }
                                break;
                        case CRTC1_TMDS | CRTC2_TMDS:   /* digital panels on both heads */
                        case CRTC1_VGA | CRTC2_VGA:             /* analog connected screens on both heads */
                        case CRTC1_TMDS | CRTC2_VGA:    /* digital panel on head 1, analog connected screen on head 2 */
                        case CRTC1_VGA | CRTC2_TMDS:    /* analog connected screen on head 1, digital panel on head 2 */
                        default:                                                /* more than two screens connected (illegal setup) */
                                if ((si->ps.crtc1_screen.aspect < (target_aspect - 0.10)) ||
                                        (si->ps.crtc2_screen.aspect < (target_aspect - 0.10))) {
                                        LOG(4, ("PROPOSEMODE: not all connected screens are widescreen (enough) type, aborted.\n"));
                                        return B_ERROR;
                                }
                                break;
                }
        }

        /* only limit modelist if user did not explicitly block this via nv.settings
           (because of errors in monitor's EDID information returned) */
        if (si->settings.check_edid) {
                /* check if screen(s) can display the requested resolution (if we have it's EDID info)
                   note:
                   allowing 2 pixels more for horizontal display for the 1366 mode, since multiples of 8
                   are required for the CRTCs horizontal timing programming) */
                if (si->ps.crtc1_screen.have_native_edid) {
                        if ((target->timing.h_display - 2) > si->ps.crtc1_screen.timing.h_display
                                || target->timing.v_display > si->ps.crtc1_screen.timing.v_display) {
                                LOG(4, ("PROPOSEMODE: screen at crtc1 can't display requested resolution, aborted.\n"));
                                return B_ERROR;
                        }
                }
                if (si->ps.crtc2_screen.have_native_edid) {
                        if ((target->timing.h_display - 2) > si->ps.crtc2_screen.timing.h_display
                                || target->timing.v_display > si->ps.crtc2_screen.timing.v_display) {
                                LOG(4, ("PROPOSEMODE: screen at crtc2 can't display requested resolution, aborted.\n"));
                                return B_ERROR;
                        }
                }
        }

        /* validate display vs. virtual */
        if (target->timing.h_display > target->virtual_width || want_same_width)
                target->virtual_width = target->timing.h_display;
        if (target->timing.v_display > target->virtual_height || want_same_height)
                target->virtual_height = target->timing.v_display;

        /* nail virtual size and 'subsequently' calculate rowbytes */
        result = nv_general_validate_pic_size(target, &row_bytes, &acc_mode);
        if (result == B_ERROR) {
                LOG(4, ("PROPOSEMODE: could not validate virtual picture size, aborted.\n"));
                return result;
        }

        /* check if virtual_width is still within the requested limits */
        if (target->virtual_width < low->virtual_width
                || target->virtual_width > high->virtual_width) {
                status = B_BAD_VALUE;
                LOG(4, ("PROPOSEMODE: WARNING: virtual_width deviates too much\n"));
        }

        /* check if timing found is within the requested horizontal limits */
        if (target->timing.h_display < low->timing.h_display
                || target->timing.h_display > high->timing.h_display
                || target->timing.h_sync_start < low->timing.h_sync_start
                || target->timing.h_sync_start > high->timing.h_sync_start
                || target->timing.h_sync_end < low->timing.h_sync_end
                || target->timing.h_sync_end > high->timing.h_sync_end
                || target->timing.h_total < low->timing.h_total
                || target->timing.h_total > high->timing.h_total) {
                /* BWindowScreen workaround: we accept everything except h_display deviations */
                if (target->timing.h_display < low->timing.h_display
                        || target->timing.h_display > high->timing.h_display)
                        status = B_BAD_VALUE;

                LOG(4, ("PROPOSEMODE: WARNING: horizontal timing deviates too much\n"));
        }

        /* check if timing found is within the requested vertical limits */
        if (target->timing.v_display < low->timing.v_display
                || target->timing.v_display > high->timing.v_display
                || target->timing.v_sync_start < low->timing.v_sync_start
                || target->timing.v_sync_start > high->timing.v_sync_start
                || target->timing.v_sync_end < low->timing.v_sync_end
                || target->timing.v_sync_end > high->timing.v_sync_end
                || target->timing.v_total < low->timing.v_total
                || target->timing.v_total > high->timing.v_total) {
                /* BWindowScreen workaround: we accept everything except v_display deviations */
                if (target->timing.v_display < low->timing.v_display
                        || target->timing.v_display > high->timing.v_display)
                        status = B_BAD_VALUE;

                LOG(4, ("PROPOSEMODE: WARNING: vertical timing deviates too much\n"));
        }

        /* adjust pixelclock for possible timing modifications done above */
        target->timing.pixel_clock = target_refresh * ((double)target->timing.h_total)
                * ((double)target->timing.v_total) / 1000.0;

        /* Now find the nearest valid pixelclock we actually can setup for the target mode,
         * this also makes sure we don't generate more pixel bandwidth than the device can handle */
        /* calculate settings, but do not actually test anything (that costs too much time!) */
        result = head1_pix_pll_find(*target, &pix_clock_found, &m, &n, &p, 0);
        /* update the target mode */
        target->timing.pixel_clock = pix_clock_found * 1000;

        /* note if we fell outside the limits */
        if (target->timing.pixel_clock < low->timing.pixel_clock
                || target->timing.pixel_clock > high->timing.pixel_clock) {
                /* BWindowScreen workaround: we accept deviations <= 1Mhz */
                if (target->timing.pixel_clock < low->timing.pixel_clock - 1000
                        || target->timing.pixel_clock > high->timing.pixel_clock + 1000)
                        status = B_BAD_VALUE;

                LOG(4, ("PROPOSEMODE: WARNING: pixelclock deviates too much\n"));
        }

        mem_reservation = 0;
        /* checkout space needed for hardcursor (if any) */
        if (si->settings.hardcursor)
                mem_reservation = 2048;

        /* Reserve extra space as a workaround for certain bugs (see DriverInterface.h
         * for an explanation). */
        if (si->ps.card_arch < NV40A)
                mem_reservation += PRE_NV40_OFFSET;
        else
                mem_reservation += NV40_PLUS_OFFSET;

        /* memory requirement for frame buffer */
        if (row_bytes * target->virtual_height > si->ps.memory_size - mem_reservation) {
                target->virtual_height = (si->ps.memory_size - mem_reservation) / row_bytes;
        }
        if (target->virtual_height < target->timing.v_display) {
                LOG(4,("PROPOSEMODE: not enough memory for current mode, aborted.\n"));
                return B_ERROR;
        }

        LOG(4,("PROPOSEMODE: validated virtual_width %d, virtual_height %d pixels\n",
                target->virtual_width, target->virtual_height));

        if (target->virtual_height < low->virtual_height
                || target->virtual_height > high->virtual_height) {
                status = B_BAD_VALUE;
                LOG(4, ("PROPOSEMODE: WARNING: virtual_height deviates too much\n"));
        }

        /* setup status flags */ 
        LOG(1, ("PROPOSEMODE: initial modeflags: $%08x\n", target->flags));
        /* preset to singlehead card without TVout, no overlay support and no hardcursor.
         * also advice system that app_server and acc engine may touch the framebuffer
         * simultaneously (fixed). */
        target->flags &=
                ~(DUALHEAD_CAPABLE | TV_CAPABLE | B_SUPPORTS_OVERLAYS | B_HARDWARE_CURSOR | B_IO_FB_NA);
        /* we always allow parallel access (fixed), the DAC is always in 'enhanced'
         * mode (fixed), and all modes support DPMS (fixed);
         * We support scrolling and panning in every mode, so we 'send a signal' to
         * BWindowScreen.CanControlFrameBuffer() by setting B_SCROLL.  */
        /* BTW: B_PARALLEL_ACCESS in combination with a hardcursor enables
         * BDirectWindow windowed modes. */
        target->flags |= (B_PARALLEL_ACCESS | B_8_BIT_DAC | B_DPMS | B_SCROLL);

        /* determine the 'would be' max. pixelclock for the second DAC for the current videomode if dualhead were activated */
        switch (target->space) {
                case B_CMAP8:
                        max_vclk = si->ps.max_dac2_clock_8;
                        bpp = 1;
                        break;
                case B_RGB15_LITTLE:
                case B_RGB16_LITTLE:
                        max_vclk = si->ps.max_dac2_clock_16;
                        bpp = 2;
                        break;
                case B_RGB24_LITTLE:
                        max_vclk = si->ps.max_dac2_clock_24;
                        bpp = 3;
                        break;
                case B_RGB32_LITTLE:
                        max_vclk = si->ps.max_dac2_clock_32dh;
                        bpp = 4;
                        break;
                default:
                        /* use fail-safe value */
                        max_vclk = si->ps.max_dac2_clock_32dh;
                        bpp = 4;
                        break;
        }

        /* set DUALHEAD_CAPABLE if suitable */
        //fixme: update for independant secondary head use! (reserve fixed memory then)
        if (si->ps.secondary_head && target->timing.pixel_clock <= (max_vclk * 1000)) {
                switch (target->flags & DUALHEAD_BITS) {
                        case DUALHEAD_ON:
                        case DUALHEAD_SWITCH:
                                if (si->ps.memory_size - mem_reservation
                                                >= row_bytes * target->virtual_height
                                        && (uint16)(row_bytes / bpp) >= target->timing.h_display * 2)
                                        target->flags |= DUALHEAD_CAPABLE;
                                break;
                        case DUALHEAD_CLONE:
                                if (si->ps.memory_size - mem_reservation
                                                >= row_bytes * target->virtual_height)
                                        target->flags |= DUALHEAD_CAPABLE;
                                break;
                        case DUALHEAD_OFF:
                                if (si->ps.memory_size - mem_reservation
                                                >= row_bytes * target->virtual_height * 2)
                                        target->flags |= DUALHEAD_CAPABLE;
                                break;
                }
        }

        /* if not dualhead capable card clear dualhead flags */
        if (!(target->flags & DUALHEAD_CAPABLE))
                target->flags &= ~DUALHEAD_BITS;

        /* set TV_CAPABLE if suitable: pixelclock is not important (defined by TVstandard) */
        if (si->ps.tvout && BT_check_tvmode(*target))
                target->flags |= TV_CAPABLE;

        /* if not TVout capable card clear TVout flags */
        if (!(target->flags & TV_CAPABLE))
                target->flags &= ~TV_BITS;

        /* make sure TV head assignment is sane */
        if (target->flags & TV_BITS) {
                if (!si->ps.secondary_head)
                        target->flags |= TV_PRIMARY;
                else if ((target->flags & DUALHEAD_BITS) == DUALHEAD_OFF)
                        target->flags |= TV_PRIMARY;
        } else
                target->flags &= ~TV_PRIMARY;

        /* set HARDWARE_CURSOR mode if suitable */
        if (si->settings.hardcursor)
                target->flags |= B_HARDWARE_CURSOR;

        /* set SUPPORTS_OVERLAYS if suitable */
        if (si->ps.card_type <= NV40 || si->ps.card_type == NV45)
                target->flags |= B_SUPPORTS_OVERLAYS;

        LOG(1, ("PROPOSEMODE: validated modeflags: $%08x\n", target->flags));

        /* overrule timing command flags to be (fixed) blank_pedestal = 0.0IRE,
         * progressive scan (fixed), and sync_on_green not avaible. */
        target->timing.flags &= ~(B_BLANK_PEDESTAL | B_TIMING_INTERLACED | B_SYNC_ON_GREEN);
        /* The HSYNC and VSYNC command flags are actually executed by the driver. */

        if (status == B_OK)
                LOG(4, ("PROPOSEMODE: completed successfully.\n"));
        else
                LOG(4, ("PROPOSEMODE: mode can be made, but outside given limits.\n"));
        return status;
}


/*!
        Return the number of modes this device will return from GET_MODE_LIST().  
        This is precalculated in create_mode_list (called from InitAccelerant stuff)
*/
uint32
ACCELERANT_MODE_COUNT(void)
{
        LOG(1, ("ACCELERANT_MODE_COUNT: the modelist contains %d modes\n",si->mode_count));
        return si->mode_count;
}


/*! Copy the list of guaranteed supported video modes to the location provided.
*/
status_t
GET_MODE_LIST(display_mode *dm)
{
        LOG(1, ("GET_MODE_LIST: exporting the modelist created before.\n"));

        memcpy(dm, my_mode_list, si->mode_count * sizeof(display_mode));
        return B_OK;
}


static void checkAndAddMode(const display_mode *src, display_mode *dst)
{
        uint32 j, pix_clk_range;
        display_mode low, high;
        color_space spaces[4] = {B_RGB32_LITTLE, B_RGB16_LITTLE, B_RGB15_LITTLE, B_CMAP8};

        /* set ranges for acceptable values */
        low = high = *src;
        /* range is 6.25% of default clock: arbitrarily picked */ 
        pix_clk_range = low.timing.pixel_clock >> 5;
        low.timing.pixel_clock -= pix_clk_range;
        high.timing.pixel_clock += pix_clk_range;
        /* 'some cards need wider virtual widths for certain modes':
         * Not true. They might need a wider pitch, but this is _not_ reflected in
         * virtual_width, but in fbc.bytes_per_row. */
        //So disable next line: 
        //high.virtual_width = 4096;
        /* do it once for each depth we want to support */
        for (j = 0; j < (sizeof(spaces) / sizeof(color_space)); j++) {
                /* set target values */
                dst[si->mode_count] = *src;
                /* poke the specific space */
                dst[si->mode_count].space = low.space = high.space = spaces[j];
                /* ask for a compatible mode */
                /* We have to check for B_OK, because otherwise the pix_clk_range
                 * won't be taken into account!! */
                //So don't do this: 
                //if (PROPOSE_DISPLAY_MODE(dst, &low, &high) != B_ERROR) {
                //Instead, do this:
                if (PROPOSE_DISPLAY_MODE(&dst[si->mode_count], &low, &high) == B_OK) {
                        /* count it, so move on to next mode */
                        si->mode_count++;
                }
        }
}


/*! Create a list of display_modes to pass back to the caller.
*/
status_t
create_mode_list(void)
{
        size_t max_size;
        uint32 i;
        const display_mode *src;
        display_mode *dst;
        display_mode custom_mode;

        /* figure out how big the list could be (4 colorspaces, 3 virtual types per mode), and adjust up to nearest multiple of B_PAGE_SIZE */
        max_size = (((MODE_COUNT * 4 * 3) * sizeof(display_mode)) + (B_PAGE_SIZE-1)) & ~(B_PAGE_SIZE-1);

        /* create an area to hold the info */
        si->mode_area = my_mode_list_area = create_area("NV accelerant mode info",
                (void **)&my_mode_list, B_ANY_ADDRESS, max_size, B_NO_LOCK,
                B_READ_AREA | B_WRITE_AREA | B_CLONEABLE_AREA);
        if (my_mode_list_area < B_OK)
                return my_mode_list_area;

        /* walk through our predefined list and see which modes fit this device */
        src = mode_list;
        dst = my_mode_list;
        si->mode_count = 0;
        for (i = 0; i < MODE_COUNT; i++) {
                // standard mode
                /* unfortunately Haiku's screenprefs panel does not support single head output explicitly, so we'd better
                   activate both heads always to (probably) mimic Radeon driver behaviour (for which this app was adapted) */
                /* note please:
                   - this will have a big downside on hardware for which both heads have different resolution cababilities (i.e. Matrox);
                   - also (on laptops) this will shorten battery life a bit of course.. */
                custom_mode = *src;
                custom_mode.flags |= DUALHEAD_CLONE;
                checkAndAddMode(&custom_mode, dst);
                // double width mode for Haiku ScreenPrefs panel
                /* note please: These modes should not be added. Instead the mode.flags should be used during setting screen as these will
                   automatically generate the needed other properties of the mode. Besides, virtual size is meant to be used for
                   pan&scan modes (viewports), i.e. for certain games.
                   The currently used method will fail programs that are meant to work pan@scan if the virtual width (or height) are
                   exactly twice the view area. */
                custom_mode = *src;
                custom_mode.virtual_width *= 2;
                custom_mode.flags |= DUALHEAD_ON;
                checkAndAddMode(&custom_mode, dst);
                // we don't support double height modes
                /* advance to next mode */
                src++;
        }

        return B_OK;
}