From: Helge Deller <deller@gmx.de>
To: Steffen Persvold <spersvold@gmail.com>
Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fbdev: modedb: Fix misaligned fields in the 1920x1080-60 mode
Date: Fri, 12 Jun 2026 23:22:56 +0200 [thread overview]
Message-ID: <628300b8-ff6e-46e4-961c-222c93fbec3c@gmx.de> (raw)
In-Reply-To: <20260612164041.3652599-1-spersvold@gmail.com>
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 <spersvold@gmail.com>
> ---
> 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
prev parent reply other threads:[~2026-06-12 21:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-12 16:40 Steffen Persvold
2026-06-12 21:22 ` Helge Deller [this message]
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