[Intel-gfx] [PATCH v2 rebased 10/11] drm/i915/display: Check if pipe fastset is allowed by external dependencies

[Souza, Jose]

On Thu, 2019-12-12 at 23:28 +0200, Ville Syrjälä wrote:
> On Wed, Dec 11, 2019 at 10:45:25AM -0800, José Roberto de Souza
> wrote:
> > Check if fastset is allowed by external dependencies like other
> > pipes
> > and transcoders.
> > 
> > Right now it only forces a fullmodeset when the MST master
> > transcoder
> > did not changed but the pipe of the master transcoder needs a
> > fullmodeset so all slaves also needs to do a fullmodeset.
> > But it will probably be need for port sync as well.
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 41
> > ++++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 092412b10d7c..0c24d7dfa152 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -13930,11 +13930,52 @@ static int calc_watermark_data(struct
> > intel_atomic_state *state)
> >  	return 0;
> >  }
> >  
> > +/**
> > + * Check if fastset is allowed by external dependencies like other
> > pipes and
> > + * transcoders.
> > + *
> > + * Right now it only forces a fullmodeset when the MST master
> > transcoder did
> > + * not changed but the pipe of the master transcoder needs a
> > fullmodeset so
> > + * all slaves also needs to do a fullmodeset.
> > + */
> > +static bool
> > +intel_crtc_check_external_dependencies_fastset(const struct
> > intel_crtc_state *old_crtc_state,
> > +					       struct intel_crtc_state
> > *new_crtc_state)
> > +{
> > +	struct intel_atomic_state *state =
> > to_intel_atomic_state(new_crtc_state->uapi.state);
> > +	struct drm_i915_private *dev_priv = to_i915(new_crtc_state-
> > >uapi.crtc->dev);
> > +	struct intel_crtc_state *new_crtc_state_iter;
> > +	struct intel_crtc *crtc_iter;
> > +	int i;
> > +
> > +	if (INTEL_GEN(dev_priv) < 12)
> > +		return true;
> > +
> > +	if (!intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DP_MST)
> > ||
> > +	    intel_dp_mst_is_master_trans(new_crtc_state))
> > +		return true;
> > +
> > +	for_each_new_intel_crtc_in_state(state, crtc_iter,
> > new_crtc_state_iter, i) {
> > +		if (new_crtc_state_iter->cpu_transcoder !=
> > +		    new_crtc_state->mst_master_transcoder)
> > +			continue;
> > +
> > +		return !needs_modeset(new_crtc_state_iter);
> > +	}
> > +
> > +	DRM_ERROR("Master MST transcoder of pipe not found\n");
> > +	return false;
> > +}
> > +
> >  static void intel_crtc_check_fastset(const struct intel_crtc_state
> > *old_crtc_state,
> >  				     struct intel_crtc_state
> > *new_crtc_state)
> >  {
> >  	if (!intel_pipe_config_compare(old_crtc_state, new_crtc_state,
> > true))
> >  		return;
> > +	if
> > (!intel_crtc_check_external_dependencies_fastset(old_crtc_state,
> > +							    new_crtc_st
> > ate))
> > +		return;
> 
> I don't think this will work. We've not yet .compute_config()'d
> everything so the master assignments are still up in the air.

As the MST master is the smallest pipe/transcoder id it is computed
first, so it works for MST but that is not the port sync case.
Will do a suggested bellow to already support port sync.


> 
> I think we need the logic higher up in intel_atomic_check():
> 
> for_each_crtc()
> 	compute_config()
> 	if (can_fastset())
> 		needs_modeset=false
> 		update_pipe=true;
> 	}
> }
> 
> for_each_crtc()
> 	if (mst_slave && master.needs_modeset() {
> 		needs_modeset=true;
> 		update_pipe=false;
> 	}
> 
> for_each_crtc()
> 	if (update_pipe)
> 		copy_over_old_state();
> 
> 	
> + we should probably rename/split update_pipes or add some
> lkind of needs_fastset() wrapper to make this less confusing.
> 
> 
> > +
> >  
> >  	new_crtc_state->uapi.mode_changed = false;
> >  	new_crtc_state->update_pipe = true;
> > -- 
> > 2.24.1