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

[Wakko Warner]

Thomas Zimmermann wrote:
> 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?

You may.

> > > 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)
> 
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