Thread (2 messages) 2 messages, 2 authors, 24d ago

Re: [PATCH] fbdev: modedb: Fix misaligned fields in the 1920x1080-60 mode

From: Helge Deller <deller@gmx.de>
Date: 2026-06-12 21:22:58
Also in: dri-devel, lkml

On 6/12/26 18:40, Steffen Persvold wrote:
The 1920x1080@60 modedb entry has one too many initializers before
its sync field: a stray "0" occupies the sync slot, which shifts the
remaining values by one field. The entry therefore decodes as
sync = 0, vmode = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT (0x3,
i.e. FB_VMODE_INTERLACED | FB_VMODE_DOUBLE), and flag =
FB_VMODE_NONINTERLACED, instead of the intended sync = positive H/V,
vmode = non-interlaced.

fb_find_mode() then returns a 1920x1080 mode flagged as interlaced +
doublescan with active-low syncs. Drivers that honour var->vmode and
var->sync when programming display timing enable doublescan and the
wrong sync polarity, corrupting the output.

Drop the stray initializer so sync and vmode hold their intended
values (positive H/V sync, non-interlaced), matching the adjacent
1920x1200 entry.

Fixes: c8902258b2b8 ("fbdev: modedb: Add 1920x1080 at 60 Hz video mode")
Cc: stable@vger.kernel.org
Signed-off-by: Steffen Persvold <redacted>
---
  drivers/video/fbdev/core/modedb.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
Steffen, thanks for fixing the bug which was actually introduced by me!

This patch is now applied to the fbdev git tree.

Thanks!
Helge
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