[PATCH] drm/mgag200: Fix value in <VBLKSTR> register

[Thomas Zimmermann]

Hi

Am 16.04.25 um 17:22 schrieb Wakko Warner:
> Thomas Zimmermann wrote:
>> Fix an off-by-one error when setting the vblanking start in
>> <VBLKSTR>. Commit d6460bd52c27 ("drm/mgag200: Add dedicated
>> variables for blanking fields") switched the value from
>> crtc_vdisplay to crtc_vblank_start, which DRM helpers copy
>> from the former. The commit missed to subtract one though.
> Applied to 6.14.2.  BMC and external monitor works as expected.

Great. Thanks for testing. Can I add your Tested-by tag to the commit?

Best regards
Thomas

>
> Thank you.
>
>> Reported-by: Wakko Warner <wakko at animx.eu.org>
>> Closes: https://lore.kernel.org/dri-devel/CAMwc25rKPKooaSp85zDq2eh-9q4UPZD=RqSDBRp1fAagDnmRmA@mail.gmail.com/
>> Reported-by: ???????????? <afmerlord at gmail.com>
>> Closes: https://lore.kernel.org/all/5b193b75-40b1-4342-a16a-ae9fc62f245a@gmail.com/
>> Closes: https://bbs.archlinux.org/viewtopic.php?id=303819
>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>> Fixes: d6460bd52c27 ("drm/mgag200: Add dedicated variables for blanking fields")
>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
>> Cc: Jocelyn Falempe <jfalempe at redhat.com>
>> Cc: Dave Airlie <airlied at redhat.com>
>> Cc: dri-devel at lists.freedesktop.org
>> Cc: <stable at vger.kernel.org> # v6.12+
>> ---
>>   drivers/gpu/drm/mgag200/mgag200_mode.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
>> index fb71658c3117..6067d08aeee3 100644
>> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
>> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
>> @@ -223,7 +223,7 @@ void mgag200_set_mode_regs(struct mga_device *mdev, const struct drm_display_mod
>>   	vsyncstr = mode->crtc_vsync_start - 1;
>>   	vsyncend = mode->crtc_vsync_end - 1;
>>   	vtotal = mode->crtc_vtotal - 2;
>> -	vblkstr = mode->crtc_vblank_start;
>> +	vblkstr = mode->crtc_vblank_start - 1;
>>   	vblkend = vtotal + 1;
>>   
>>   	linecomp = vdispend;
>> -- 
>> 2.49.0
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)