Re: [PATCH] drm/tilcdc: send vblank event when disabling crtc

[quanyang.wang]

Ping.

On 1/29/21 3:58 PM, Tomi Valkeinen wrote:
> Dropped the @ti.com addresses and added the new ones.
>
>   Tomi
>
> On 29/01/2021 07:58, quanyang.wang@xxxxxxxxxxxxx wrote:
> > From: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>
> >
> > When run xrandr to change resolution on Beaglebone Black board, it will
> > print the error information:
> >
> > root@beaglebone:~# xrandr -display :0 --output HDMI-1 --mode 720x400
> > [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
> > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:32:tilcdc crtc] commit wait timed out
> > [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
> > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:34:HDMI-A-1] commit wait timed out
> > [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
> > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:31:plane-0] commit wait timed out
> > tilcdc 4830e000.lcdc: already pending page flip!
> >
> > This is because there is operation sequence as below:
> >
> > drm_atomic_connector_commit_dpms(mode is DRM_MODE_DPMS_OFF):
> >      ...
> >      drm_atomic_helper_setup_commit <- init_completion(commit_A->flip_done)
> >      drm_atomic_helper_commit_tail
> >          tilcdc_crtc_atomic_disable
> >          tilcdc_plane_atomic_update <- drm_crtc_send_vblank_event in tilcdc_crtc_irq
> >                                        is skipped since tilcdc_crtc->enabled is 0
> >          tilcdc_crtc_atomic_flush   <- drm_crtc_send_vblank_event is skipped since
> >                                        crtc->state->event is set to be NULL in
> >                                        tilcdc_plane_atomic_update
> > drm_mode_setcrtc:
> >      ...
> >      drm_atomic_helper_setup_commit <- init_completion(commit_B->flip_done)
> >      drm_atomic_helper_wait_for_dependencies
> >          drm_crtc_commit_wait   <- wait for commit_A->flip_done completing
> >
> > Just as shown above, the steps which could complete commit_A->flip_done
> > are all skipped and commit_A->flip_done will never be completed. This will
> > result a time-out ERROR when drm_crtc_commit_wait check the commit_A->flip_done.
> > So add drm_crtc_send_vblank_event in tilcdc_crtc_atomic_disable to
> > complete commit_A->flip_done.
> >
> > Fixes: cb345decb4d2 ("drm/tilcdc: Use standard drm_atomic_helper_commit")
> > Signed-off-by: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> > index 30213708fc99..d99afd19ca08 100644
> > --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> > +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
> > @@ -515,6 +515,15 @@ static void tilcdc_crtc_off(struct drm_crtc *crtc, bool shutdown)
> >   
> >   	drm_crtc_vblank_off(crtc);
> >   
> > +	spin_lock_irq(&crtc->dev->event_lock);
> > +
> > +	if (crtc->state->event) {
> > +		drm_crtc_send_vblank_event(crtc, crtc->state->event);
> > +		crtc->state->event = NULL;
> > +	}
> > +
> > +	spin_unlock_irq(&crtc->dev->event_lock);
> > +
> >   	tilcdc_crtc_disable_irqs(dev);
> >   
> >   	pm_runtime_put_sync(dev->dev);