From: Ville Syrjälä ville.syrjala@linux.intel.com
The DispID DTD pixel clock is documented as: "00 00 00 h → FF FF FF h | Pixel clock ÷ 10,000 0.01 → 167,772.16 Mega Pixels per Sec" Which seems to imply that we to add one to the raw value.
Reality seems to agree as there are tiled displays in the wild which currently show a 10kHz difference in the pixel clock between the tiles (one tile gets its mode from the base EDID, the other from the DispID block).
Cc: stable@vger.kernel.org References: https://gitlab.freedesktop.org/drm/intel/-/issues/27 Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_edid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 43b6ca364daa..544d2603f5fc 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5120,7 +5120,7 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d struct drm_display_mode *mode; unsigned pixel_clock = (timings->pixel_clock[0] | (timings->pixel_clock[1] << 8) | - (timings->pixel_clock[2] << 16)); + (timings->pixel_clock[2] << 16)) + 1; unsigned hactive = (timings->hactive[0] | timings->hactive[1] << 8) + 1; unsigned hblank = (timings->hblank[0] | timings->hblank[1] << 8) + 1; unsigned hsync = (timings->hsync[0] | (timings->hsync[1] & 0x7f) << 8) + 1;
On Thu, Apr 23, 2020 at 06:17:43PM +0300, Ville Syrjala wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
The DispID DTD pixel clock is documented as: "00 00 00 h → FF FF FF h | Pixel clock ÷ 10,000 0.01 → 167,772.16 Mega Pixels per Sec" Which seems to imply that we to add one to the raw value.
Reality seems to agree as there are tiled displays in the wild which currently show a 10kHz difference in the pixel clock between the tiles (one tile gets its mode from the base EDID, the other from the DispID block).
Cc: stable@vger.kernel.org References: https://gitlab.freedesktop.org/drm/intel/-/issues/27 Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Makes total sense,
Reviewed-by: Manasi Navare manasi.d.navare@intel.com
Manasi
drivers/gpu/drm/drm_edid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 43b6ca364daa..544d2603f5fc 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5120,7 +5120,7 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d struct drm_display_mode *mode; unsigned pixel_clock = (timings->pixel_clock[0] | (timings->pixel_clock[1] << 8) |
(timings->pixel_clock[2] << 16));
(timings->pixel_clock[2] << 16)) + 1;-- 2.24.1
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