[Intel-gfx] [PATCH v4 15/18] drm/i915/display: Helpers for VRR vblank min and max start

[Navare, Manasi]

Yes will drop that TODO

Also,

Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>

Manasi


On Tue, Jan 19, 2021 at 09:07:56PM +0200, Ville Syrjälä wrote:
> On Wed, Jan 13, 2021 at 02:09:32PM -0800, Manasi Navare wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > With VRR the earliest the registers can get latched are at
> > flipline decision boundary, calculate that as vrr_vmin_vblank_start()
> > and the latest the regsiters can get latched are vmax decision boundary
> > calculate that as vrr_vmax_vblank_start()
> > 
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_vrr.c | 36 ++++++++++++++++++++++++
> >  drivers/gpu/drm/i915/display/intel_vrr.h |  2 ++
> >  2 files changed, 38 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> > index 5dc6d578760a..9a18c36e4a9a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> > @@ -45,6 +45,42 @@ intel_vrr_check_modeset(struct intel_atomic_state *state)
> >  	}
> >  }
> >  
> > +/*
> > + * Without VRR registers get latched at:
> > + *  vblank_start
> > + *
> > + * With VRR the earliest registers can get latched is:
> > + *  intel_vrr_vmin_vblank_start(), which if we want to maintain
> > + *  the correct min vtotal is >=vblank_start+1
> > + *
> > + * The latest point registers can get latched is the vmax decision boundary:
> > + *  intel_vrr_vmax_vblank_start()
> > + *
> > + * Between those two points the vblank exit starts (and hence registers get
> > + * latched) ASAP after a push is sent.
> > + *
> > + * framestart_delay is programmable 0-3.
> > + */
> > +static int intel_vrr_vblank_exit_length(const struct intel_crtc_state *crtc_state)
> > +{
> > +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> > +
> > +	/* TODO: Not sure why the hw imposes the extra scanline?, also check on TGL */
> 
> We can now drop the TGL TODO(s) since I tested it and confirmed it
> follows the same rules.
> 
> > +	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 2;
> > +}
> > +
> > +int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state)
> > +{
> > +	/* Min vblank actually determined by flipline that is always >=vmin+1 */
> > +	return crtc_state->vrr.vmin + 1 - intel_vrr_vblank_exit_length(crtc_state);
> > +}
> > +
> > +int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state)
> > +{
> > +	return crtc_state->vrr.vmax - intel_vrr_vblank_exit_length(crtc_state);
> > +}
> > +
> >  void
> >  intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
> >  			 struct drm_connector_state *conn_state)
> > diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
> > index 7610051edad2..d8b6b45557ca 100644
> > --- a/drivers/gpu/drm/i915/display/intel_vrr.h
> > +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
> > @@ -27,5 +27,7 @@ void intel_vrr_send_push(const struct intel_crtc_state *crtc_state);
> >  void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state);
> >  void intel_vrr_get_config(struct intel_crtc *crtc,
> >  			  struct intel_crtc_state *crtc_state);
> > +int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state);
> > +int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state);
> >  
> >  #endif /* __INTEL_VRR_H__ */
> > -- 
> > 2.19.1
> 
> -- 
> Ville Syrjälä
> Intel