Re: [PATCH v2 5/9] drm/i915/display: Fix glitches when moving cursor with PSR2 selective fetch enabled

[Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>]

Looks good to me.
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>


On 9/30/21 10:56 AM, Ville Syrjälä wrote:
> On Wed, Sep 29, 2021 at 05:14:05PM -0700, José Roberto de Souza wrote:
> > Legacy cursor APIs are handled by intel_legacy_cursor_update(), that
> > calls drm_atomic_helper_update_plane() when going through the
> > slow/atomic path to update cursor, what was the case for PSR2
> > selective fetch.
> >
> > drm_atomic_helper_update_plane() sets
> > drm_atomic_state->legacy_cursor_update to true when updating the
> > cursor plane, to allow several cursor updates to happen within the
> > same frame, as userspace does that.
> > If drivers waited for a vblank increment at the end of every cursor
> > movement that would cause a visible lag in the cursor.
> >
> > But this optimization do not properly work with PSR2 selective fetch
> > dirt area calculation, for example if within a single frame the cursor
> > had 3 moves the final dirt area programmed to PSR2_MAN_TRK_CTL would
> > be based in the second movement as old state and third movement as new
> > state, not updating the area where cursor was in the first state.
> >
> > So here switching back to the fast path approach in
> > intel_legacy_cursor_update() and handling cursor movements as
> > frontbuffer rendering(psr_force_hw_tracking_exit()), that is not the
> > most optimal for power-savings but is the solution that we have until
> > mailbox style updates is implemented.
> >
> > Also removing the cursor workaround as not it is properly undestand
> > the issue and is know that it will never cover all the cases.
> >
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>
> > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
>
> Not really familiar with the PSR details to give a full review
> on those parts, but the approach looks OK to me.
>
> Acked-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> > ---
> >   drivers/gpu/drm/i915/display/intel_cursor.c   |  5 +-
> >   drivers/gpu/drm/i915/display/intel_fbc.c      |  4 +-
> >   .../gpu/drm/i915/display/intel_frontbuffer.h  |  1 +
> >   drivers/gpu/drm/i915/display/intel_psr.c      | 59 +++++--------------
> >   4 files changed, 20 insertions(+), 49 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
> > index 901ad3a4c8c3b..f6dcb5aa63f64 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cursor.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cursor.c
> > @@ -639,8 +639,7 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
> >   	 * FIXME bigjoiner fastpath would be good
> >   	 */
> >   	if (!crtc_state->hw.active || intel_crtc_needs_modeset(crtc_state) ||
> > -	    crtc_state->update_pipe || crtc_state->bigjoiner ||
> > -	    crtc_state->enable_psr2_sel_fetch)
> > +	    crtc_state->update_pipe || crtc_state->bigjoiner)
> >   		goto slow;
> >   
> >   	/*
> > @@ -698,7 +697,7 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
> >   		goto out_free;
> >   
> >   	intel_frontbuffer_flush(to_intel_frontbuffer(new_plane_state->hw.fb),
> > -				ORIGIN_FLIP);
> > +				ORIGIN_CURSOR_UPDATE);
> >   	intel_frontbuffer_track(to_intel_frontbuffer(old_plane_state->hw.fb),
> >   				to_intel_frontbuffer(new_plane_state->hw.fb),
> >   				plane->frontbuffer_bit);
> > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> > index 46f62fdf9eeeb..77b00e3a92c23 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> > @@ -1199,7 +1199,7 @@ void intel_fbc_invalidate(struct drm_i915_private *dev_priv,
> >   	if (!HAS_FBC(dev_priv))
> >   		return;
> >   
> > -	if (origin == ORIGIN_FLIP)
> > +	if (origin == ORIGIN_FLIP || origin == ORIGIN_CURSOR_UPDATE)
> >   		return;
> >   
> >   	mutex_lock(&fbc->lock);
> > @@ -1224,7 +1224,7 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv,
> >   
> >   	fbc->busy_bits &= ~frontbuffer_bits;
> >   
> > -	if (origin == ORIGIN_FLIP)
> > +	if (origin == ORIGIN_FLIP || origin == ORIGIN_CURSOR_UPDATE)
> >   		goto out;
> >   
> >   	if (!fbc->busy_bits && fbc->crtc &&
> > diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.h b/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > index 4b977c1e4d52b..a88441edc8f94 100644
> > --- a/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > +++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.h
> > @@ -37,6 +37,7 @@ enum fb_op_origin {
> >   	ORIGIN_CS,
> >   	ORIGIN_FLIP,
> >   	ORIGIN_DIRTYFB,
> > +	ORIGIN_CURSOR_UPDATE,
> >   };
> >   
> >   struct intel_frontbuffer {
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> > index 7185801d5deff..e8af39591dfea 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1558,28 +1558,6 @@ static void intel_psr2_sel_fetch_pipe_alignment(const struct intel_crtc_state *c
> >   		drm_warn(&dev_priv->drm, "Missing PSR2 sel fetch alignment with DSC\n");
> >   }
> >   
> > -/*
> > - * FIXME: Not sure why but when moving the cursor fast it causes some artifacts
> > - * of the cursor to be left in the cursor path, adding some pixels above the
> > - * cursor to the damaged area fixes the issue.
> > - */
> > -static void cursor_area_workaround(const struct intel_plane_state *new_plane_state,
> > -				   struct drm_rect *damaged_area,
> > -				   struct drm_rect *pipe_clip)
> > -{
> > -	const struct intel_plane *plane = to_intel_plane(new_plane_state->uapi.plane);
> > -	int height;
> > -
> > -	if (plane->id != PLANE_CURSOR)
> > -		return;
> > -
> > -	height = drm_rect_height(&new_plane_state->uapi.dst) / 2;
> > -	damaged_area->y1 -=  height;
> > -	damaged_area->y1 = max(damaged_area->y1, 0);
> > -
> > -	clip_area_update(pipe_clip, damaged_area);
> > -}
> > -
> >   /*
> >    * TODO: Not clear how to handle planes with negative position,
> >    * also planes are not updated if they have a negative X
> > @@ -1680,9 +1658,6 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
> >   				damaged_area.y2 = new_plane_state->uapi.dst.y2;
> >   				clip_area_update(&pipe_clip, &damaged_area);
> >   			}
> > -
> > -			cursor_area_workaround(new_plane_state, &damaged_area,
> > -					       &pipe_clip);
> >   			continue;
> >   		} else if (new_plane_state->uapi.alpha != old_plane_state->uapi.alpha) {
> >   			/* If alpha changed mark the whole plane area as damaged */
> > @@ -2116,20 +2091,16 @@ void intel_psr_invalidate(struct drm_i915_private *dev_priv,
> >   /*
> >    * When we will be completely rely on PSR2 S/W tracking in future,
> >    * intel_psr_flush() will invalidate and flush the PSR for ORIGIN_FLIP
> > - * event also therefore tgl_dc3co_flush() require to be changed
> > + * event also therefore tgl_dc3co_flush_locked() require to be changed
> >    * accordingly in future.
> >    */
> >   static void
> > -tgl_dc3co_flush(struct intel_dp *intel_dp, unsigned int frontbuffer_bits,
> > -		enum fb_op_origin origin)
> > +tgl_dc3co_flush_locked(struct intel_dp *intel_dp, unsigned int frontbuffer_bits,
> > +		       enum fb_op_origin origin)
> >   {
> > -	mutex_lock(&intel_dp->psr.lock);
> > -
> > -	if (!intel_dp->psr.dc3co_exitline)
> > -		goto unlock;
> > -
> > -	if (!intel_dp->psr.psr2_enabled || !intel_dp->psr.active)
> > -		goto unlock;
> > +	if (!intel_dp->psr.dc3co_exitline || !intel_dp->psr.psr2_enabled ||
> > +	    !intel_dp->psr.active)
> > +		return;
> >   
> >   	/*
> >   	 * At every frontbuffer flush flip event modified delay of delayed work,
> > @@ -2137,14 +2108,11 @@ tgl_dc3co_flush(struct intel_dp *intel_dp, unsigned int frontbuffer_bits,
> >   	 */
> >   	if (!(frontbuffer_bits &
> >   	    INTEL_FRONTBUFFER_ALL_MASK(intel_dp->psr.pipe)))
> > -		goto unlock;
> > +		return;
> >   
> >   	tgl_psr2_enable_dc3co(intel_dp);
> >   	mod_delayed_work(system_wq, &intel_dp->psr.dc3co_work,
> >   			 intel_dp->psr.dc3co_exit_delay);
> > -
> > -unlock:
> > -	mutex_unlock(&intel_dp->psr.lock);
> >   }
> >   
> >   /**
> > @@ -2169,11 +2137,6 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
> >   		unsigned int pipe_frontbuffer_bits = frontbuffer_bits;
> >   		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> >   
> > -		if (origin == ORIGIN_FLIP) {
> > -			tgl_dc3co_flush(intel_dp, frontbuffer_bits, origin);
> > -			continue;
> > -		}
> > -
> >   		mutex_lock(&intel_dp->psr.lock);
> >   		if (!intel_dp->psr.enabled) {
> >   			mutex_unlock(&intel_dp->psr.lock);
> > @@ -2194,6 +2157,14 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
> >   			continue;
> >   		}
> >   
> > +		if (origin == ORIGIN_FLIP ||
> > +		    (origin == ORIGIN_CURSOR_UPDATE &&
> > +		     !intel_dp->psr.psr2_sel_fetch_enabled)) {
> > +			tgl_dc3co_flush_locked(intel_dp, frontbuffer_bits, origin);
> > +			mutex_unlock(&intel_dp->psr.lock);
> > +			continue;
> > +		}
> > +
> >   		/* By definition flush = invalidate + flush */
> >   		if (pipe_frontbuffer_bits)
> >   			psr_force_hw_tracking_exit(intel_dp);
> > --
> > 2.33.0