Re: [PATCH v7 13/13] drm/i915/psr: Allow DSB usage when PSR is enabled

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Wed, 2025-02-12 at 16:52 +0200, Ville Syrjälä wrote:
> On Wed, Feb 12, 2025 at 09:57:42AM +0200, Jouni Högander wrote:
> > Now as we have correct PSR2_MAN_TRK_CTL handling in place we can
> > allow DSB
> > usage also when PSR is enabled for LunarLake onwards.
> > 
> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> > Reviewed-by: Animesh Manna <animesh.manna@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 0ba85623835c..a6966a664d87 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -7698,6 +7698,7 @@ static void intel_atomic_dsb_prepare(struct
> > intel_atomic_state *state,
> >  static void intel_atomic_dsb_finish(struct intel_atomic_state
> > *state,
> >  				    struct intel_crtc *crtc)
> >  {
> > +	struct intel_display *display = to_intel_display(state);
> >  	const struct intel_crtc_state *old_crtc_state =
> >  		intel_atomic_get_old_crtc_state(state, crtc);
> >  	struct intel_crtc_state *new_crtc_state =
> > @@ -7713,7 +7714,7 @@ static void intel_atomic_dsb_finish(struct
> > intel_atomic_state *state,
> >  	new_crtc_state->use_dsb =
> >  		new_crtc_state->update_planes &&
> >  		!new_crtc_state->do_async_flip &&
> > -		!new_crtc_state->has_psr &&
> > +		(DISPLAY_VER(display) >= 20 || !new_crtc_state-
> > >has_psr) &&
> 
> Couldn't we also do it for !selective_fetch on earlier platforms?

I was thinking this as well, but I haven't tested it. I'm concerned are
of frontbuffer invalidates/flushes. There we are disabling PSR. I'm not
sure if it would be ok to do that while DSB update is ongoing.

BR,

Jouni Högander
> 
> >  		!new_crtc_state->scaler_state.scaler_users &&
> >  		!old_crtc_state->scaler_state.scaler_users &&
> >  		!intel_crtc_needs_modeset(new_crtc_state) &&
> > -- 
> > 2.43.0
>