[Intel-gfx] [PATCH] drm/i915/display: Exit PSR when doing async flips

[Souza, Jose]

On Mon, 2021-11-01 at 16:36 -0400, Rodrigo Vivi wrote:
> On Fri, Oct 29, 2021 at 05:18:01PM -0700, José Roberto de Souza wrote:
> > Changing the buffer in the middle of the scanout then entering an
> > period of flip idleness will cause part of the previous buffer being
> > diplayed to user when PSR is enabled.
> > 
> > So here disabling and scheduling activation after a few milliseconds
> > when async flip is enabled in the state.
> > 
> > The async flip check that we had in PSR compute is not executed at
> > every flip so it was not doing anything useful and is also being
> > dropped here.
> > 
> > Cc: Karthik B S <karthik.b.s at intel.com>
> > Cc: Vandita Kulkarni <vandita.kulkarni at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_psr.c | 11 +++++------
> >  1 file changed, 5 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> > index 9d589d471e335..d1301e2729553 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -731,12 +731,6 @@ static bool intel_psr2_sel_fetch_config_valid(struct intel_dp *intel_dp,
> >  		return false;
> >  	}
> >  
> > -	if (crtc_state->uapi.async_flip) {
> > -		drm_dbg_kms(&dev_priv->drm,
> > -			    "PSR2 sel fetch not enabled, async flip enabled\n");
> > -		return false;
> > -	}
> > -
> >  	/* Wa_14010254185 Wa_14010103792 */
> >  	if (IS_TGL_DISPLAY_STEP(dev_priv, STEP_A0, STEP_C0)) {
> >  		drm_dbg_kms(&dev_priv->drm,
> > @@ -1780,6 +1774,11 @@ void intel_psr_pre_plane_update(struct intel_atomic_state *state,
> >  		if (psr->enabled && needs_to_disable)
> >  			intel_psr_disable_locked(intel_dp);
> >  
> > +		if (psr->enabled && crtc_state->uapi.async_flip) {
> > +			intel_psr_exit(intel_dp);
> > +			schedule_work(&intel_dp->psr.work);
> 
> wouldn't it be better(safer?) to reschedule it back in a later stage?

good idea, do that in intel_psr_post_plane_update().

thanks

> 
> > +		}
> > +
> >  		mutex_unlock(&psr->lock);
> >  	}
> >  }
> > -- 
> > 2.33.1
> >