[PATCH] drm/i915/psr: Do not trigger Frame Change events from frontbuffer flush

[Kandpal, Suraj]

> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander at intel.com>
> Sent: Thursday, August 7, 2025 10:56 AM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>; intel-xe at lists.freedesktop.org;
> intel-gfx at lists.freedesktop.org
> Cc: janna.martl109 at gmail.com
> Subject: Re: [PATCH] drm/i915/psr: Do not trigger Frame Change events from
> frontbuffer flush
> 
> On Thu, 2025-08-07 at 04:38 +0000, Kandpal, Suraj wrote:
> > > Subject: [PATCH] drm/i915/psr: Do not trigger Frame Change events
> > > from frontbuffer flush
> > >
> > > We want to get rid of triggering "Frame Change" events from
> > > frontbuffer flush calls. We are about to move using TRANS_PUSH
> > > register for this on LunarLake and onwards. Touching TRANS_PUSH
> > > register from fronbuffer flush would be problematic as it's written
> > > by DSB as well.
> > >
> > > Fix this by using intel_psr_exit when flush or invalidate is done on
> > > LunarLake and onwards. This is not possible on AlderLake and
> > > MeteorLake due to HW bug in PSR2 disable.
> > >
> > > This patch is also fixing problems with cursor plane where cursor is
> > > disappearing or duplicate cursor is seen on the screen.
> > >
> >
> > Any Bspec link that documents this tried to look through the patch
> > series this was plucked of from
> > Didn’t find any there either.
> 
> I can add following:
> 
> Bspec: 68927, 68934, 66624
> 
> BR,
> 
> Jouni Högander
> 
> >
> > Regards,
> > Suraj Kandpal
> >
> > > v2: Commit message updated

LGTM,
Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>

> > >
> > > Reported-by: Janna Martl <janna.martl109 at gmail.com>
> > > Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/5522
> > > Fixes: 411ad63877bb ("drm/i915/psr: Use SFF_CTL on invalidate/flush
> > > for
> > > LunarLake onwards")
> > > Tested-by: Janna Martl <janna.martl109 at gmail.com>
> > > Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_psr.c | 14 +++++++++-----
> > >  1 file changed, 9 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > > b/drivers/gpu/drm/i915/display/intel_psr.c
> > > index 6bd3454bb00e..4279c28ae27c 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > > @@ -3254,7 +3254,9 @@ static void
> > > intel_psr_configure_full_frame_update(struct intel_dp *intel_dp)
> > >
> > >  static void _psr_invalidate_handle(struct intel_dp *intel_dp)  {
> > > -	if (intel_dp->psr.psr2_sel_fetch_enabled) {
> > > +	struct intel_display *display =
> > > to_intel_display(intel_dp);
> > > +
> > > +	if (DISPLAY_VER(display) < 20 && intel_dp-
> > > > psr.psr2_sel_fetch_enabled)
> > > +{
> > >  		if (!intel_dp->psr.psr2_sel_fetch_cff_enabled) {
> > >  			intel_dp->psr.psr2_sel_fetch_cff_enabled =
> > > true;
> > >  			intel_psr_configure_full_frame_update(inte
> > > l_dp);
> > > @@ -3340,7 +3342,7 @@ static void _psr_flush_handle(struct intel_dp
> > > *intel_dp)  {
> > >  	struct intel_display *display =
> > > to_intel_display(intel_dp);
> > >
> > > -	if (intel_dp->psr.psr2_sel_fetch_enabled) {
> > > +	if (DISPLAY_VER(display) < 20 && intel_dp-
> > > > psr.psr2_sel_fetch_enabled)
> > > +{
> > >  		if (intel_dp->psr.psr2_sel_fetch_cff_enabled) {
> > >  			/* can we turn CFF off? */
> > >  			if (intel_dp->psr.busy_frontbuffer_bits ==
> > > 0) @@ -
> > > 3357,11 +3359,13 @@ static void _psr_flush_handle(struct intel_dp
> > > *intel_dp)
> > >  		 * existing SU configuration
> > >  		 */
> > >  		intel_psr_configure_full_frame_update(intel_dp);
> > > -	}
> > >
> > > -	intel_psr_force_update(intel_dp);
> > > +		intel_psr_force_update(intel_dp);
> > > +	} else {
> > > +		intel_psr_exit(intel_dp);
> > > +	}
> > >
> > > -	if (!intel_dp->psr.psr2_sel_fetch_enabled && !intel_dp-
> > > >psr.active &&
> > > +	if ((!intel_dp->psr.psr2_sel_fetch_enabled ||
> > > DISPLAY_VER(display) >=
> > > +20) &&
> > >  	    !intel_dp->psr.busy_frontbuffer_bits)
> > >  		queue_work(display->wq.unordered, &intel_dp-
> > > >psr.work);  }
> > > --
> > > 2.43.0
> >