Re: [PATCH 1/2] drm/gma500: Add missing call to allow enabling vblank on psb/cdv

From: Paul Kocialkowski
Date: Thu Nov 07 2019 - 09:17:49 EST


Hi,

On Wed 06 Nov 19, 16:23, Patrik Jakobsson wrote:
> On Wed, Nov 6, 2019 at 10:44 AM Paul Kocialkowski
> <paul.kocialkowski@xxxxxxxxxxx> wrote:
> >
> > This adds a missing call to drm_crtc_vblank_on to the common DPMS helper
> > (used by poulsbo and cedartrail), which is called in the CRTC enable path.
> >
> > With that call, it becomes possible to enable vblank when needed.
> > It is already balanced by a drm_crtc_vblank_off call in the helper.
> >
> > Other platforms (oaktrail and medfield) use a dedicated DPMS helper that
> > does not have the proper vblank on/off hooks. They are not added in this
> > commit due to lack of hardware to test it with.
> >
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
>
> Don't think we ever found a need for having vblanks enabled... until
> now. I'll have a look if something can be done for Oaktrail since I
> have hw.

Neat, thanks!

IIRC the DPMS paths that don't use gma_crtc_dpms also lack the proper
drm_crtc_vblank_on/off calls so that's probably something to start with :)

Thanks for the review on these patches. I may have more fixes coming up.

Cheers,

Paul

> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@xxxxxxxxx>
>
> > ---
> > drivers/gpu/drm/gma500/gma_display.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/gma500/gma_display.c b/drivers/gpu/drm/gma500/gma_display.c
> > index e20ccb5d10fd..bc07ae2a9a1d 100644
> > --- a/drivers/gpu/drm/gma500/gma_display.c
> > +++ b/drivers/gpu/drm/gma500/gma_display.c
> > @@ -255,6 +255,8 @@ void gma_crtc_dpms(struct drm_crtc *crtc, int mode)
> > /* Give the overlay scaler a chance to enable
> > * if it's on this pipe */
> > /* psb_intel_crtc_dpms_video(crtc, true); TODO */
> > +
> > + drm_crtc_vblank_on(crtc);
> > break;
> > case DRM_MODE_DPMS_OFF:
> > if (!gma_crtc->active)
> > --
> > 2.23.0
> >

--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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