This is a note to let you know that I've just added the patch titled
drm/edid: Fix off-by-one in DispID DTD pixel clock
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-edid-fix-off-by-one-in-dispid-dtd-pixel-clock.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6292b8efe32e6be408af364132f09572aed14382 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx>
Date: Thu, 23 Apr 2020 18:17:43 +0300
Subject: drm/edid: Fix off-by-one in DispID DTD pixel clock
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From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
References: https://gitlab.freedesktop.org/drm/intel/-/issues/27
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423151743.18767-1-ville.syrjala@xxxxxxxxxxxxxxx
Reviewed-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3970,7 +3970,7 @@ static struct drm_display_mode *drm_mode
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;
Patches currently in stable-queue which might be from ville.syrjala@xxxxxxxxxxxxxxx are
queue-4.9/drm-edid-fix-off-by-one-in-dispid-dtd-pixel-clock.patch
