From 5ec7eb970df43248866bfce8d84ba1ef7f8ddf66 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 23 Apr 2020 18:17:43 +0300 Subject: [PATCH] drm/edid: Fix off-by-one in DispID DTD pixel clock MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 6292b8efe32e6be408af364132f09572aed14382 upstream. 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 Link: https://patchwork.freedesktop.org/patch/msgid/20200423151743.18767-1-ville.syrjala@linux.intel.com Reviewed-by: Manasi Navare Signed-off-by: Greg Kroah-Hartman --- 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 3f50b886..ea28493 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -4743,7 +4743,7 @@ 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; -- 2.7.4