[Intel-gfx] [PATCH v2 1/4] drm/i915/icl: Assign Master slave crtc links for Transcoder Port Sync

[Ville Syrjälä]

On Wed, Jun 12, 2019 at 11:39:03AM +0200, Maarten Lankhorst wrote:
> Op 23-04-2019 om 17:48 schreef Manasi Navare:
> > In case of tiled displays when the two tiles are sent across two CRTCs
> > over two separate DP SST connectors, we need a mechanism to synchronize
> > the two CRTCs and their corresponding transcoders.
> > So use the master-slave mode where there is one master corresponding
> > to last horizontal and vertical tile that needs to be genlocked with
> > all other slave tiles.
> > This patch identifies saves the master CRTC pointer in all the slave
> > CRTC states. This pointer is needed to select the master CRTC/transcoder
> > while configuring transcoder port sync for the corresponding slaves.
> >
> > v2:
> > * Move this to intel_mode_set_pipe_config(Jani N, Ville)
> > * Use slave_bitmask to save associated slaves in master crtc state (Ville)
> >
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Matt Roper <matthew.d.roper at intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 89 ++++++++++++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h     |  6 ++
> >  2 files changed, 95 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index b276345779e6..92dea2231499 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -11316,6 +11316,86 @@ static int icl_check_nv12_planes(struct intel_crtc_state *crtc_state)
> >  	return 0;
> >  }
> >  
> > +static int icl_add_genlock_crtcs(struct drm_crtc *crtc,
> > +				 struct intel_crtc_state *crtc_state,
> > +				 struct drm_atomic_state *state)
> > +{
> > +	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
> > +	struct drm_connector *master_connector, *connector;
> > +	struct drm_connector_state *connector_state;
> > +	struct drm_connector_list_iter conn_iter;
> > +	struct drm_crtc *master_crtc = NULL;
> > +	struct drm_crtc_state *master_crtc_state;
> > +	int i, tile_group_id;
> > +
> > +	if (INTEL_GEN(dev_priv) < 11)
> > +		return 0;
> > +
> > +	/*
> > +	 * In case of tiled displays there could be one or more slaves but there is
> > +	 * only one master. Lets make the CRTC used by the connector corresponding
> > +	 * to the last horizonal and last vertical tile a master/genlock CRTC.
> > +	 * All the other CRTCs corresponding to other tiles of the same Tile group
> > +	 * are the slave CRTCs and hold a pointer to their genlock CRTC.
> > +	 */
> > +	for_each_new_connector_in_state(state, connector, connector_state, i) {
> > +		if (connector_state->crtc != crtc)
> > +			continue;
> > +		if (!connector->has_tile)
> > +			continue;
> > +		if (connector->tile_h_loc == connector->num_h_tile - 1 &&
> > +		    connector->tile_v_loc == connector->num_v_tile - 1)
> > +			continue;
> > +		crtc_state->master_crtc = NULL;
> > +		tile_group_id = connector->tile_group->id;
> > +		drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
> > +		drm_for_each_connector_iter(master_connector, &conn_iter) {
> > +			struct drm_connector_state *master_conn_state = NULL;
> > +
> > +			if (!master_connector->has_tile)
> > +				continue;
> > +			if (master_connector->tile_h_loc != master_connector->num_h_tile - 1 ||
> > +			    master_connector->tile_v_loc != master_connector->num_v_tile - 1)
> > +				continue;
> > +			if (master_connector->tile_group->id != tile_group_id)
> > +				continue;
> > +
> > +			master_conn_state = drm_atomic_get_connector_state(state,
> > +									   master_connector);
> > +			if (IS_ERR(master_conn_state)) {
> > +				drm_connector_list_iter_end(&conn_iter);
> > +				return PTR_ERR(master_conn_state);
> > +			}
> > +			if (master_conn_state->crtc) {
> > +				master_crtc = master_conn_state->crtc;
> > +				break;
> > +			}
> > +		}
> > +		drm_connector_list_iter_end(&conn_iter);
> > +
> > +		if (!master_crtc) {
> > +			DRM_DEBUG_KMS("Could not add Master CRTC for Slave CRTC %d\n",
> > +				      connector_state->crtc->base.id);
> > +			return -EINVAL;
> > +		}
> > +
> > +		master_crtc_state = drm_atomic_get_crtc_state(state,
> > +							      master_crtc);
> > +		if (IS_ERR(master_crtc_state))
> > +			return PTR_ERR(master_crtc_state);
> > +
> > +		crtc_state->master_crtc = to_intel_crtc(master_crtc);
> > +		to_intel_crtc_state(master_crtc_state)->trans_port_sync_slaves |=
> > +			BIT(to_intel_crtc(crtc)->pipe);
> > +		DRM_DEBUG_KMS("Master CRTC = %d added for Slave CRTC = %d\n, slave bitmast = %d",
> > +			      master_crtc->base.id,
> > +			      crtc_state->base.crtc->base.id,
> > +			      to_intel_crtc_state(master_crtc_state)->trans_port_sync_slaves);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  static int intel_crtc_atomic_check(struct drm_crtc *crtc,
> >  				   struct drm_crtc_state *crtc_state)
> >  {
> > @@ -11795,6 +11875,9 @@ clear_intel_crtc_state(struct intel_crtc_state *crtc_state)
> >  	if (IS_G4X(dev_priv) ||
> >  	    IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> >  		saved_state->wm = crtc_state->wm;
> > +	if (INTEL_GEN(dev_priv) >= 11)
> > +		saved_state->trans_port_sync_slaves =
> > +			crtc_state->trans_port_sync_slaves;
> >  
> >  	/* Keep base drm_crtc_state intact, only clear our extended struct */
> >  	BUILD_BUG_ON(offsetof(struct intel_crtc_state, base));
> > @@ -11888,6 +11971,12 @@ intel_modeset_pipe_config(struct drm_crtc *crtc,
> >  	drm_mode_set_crtcinfo(&pipe_config->base.adjusted_mode,
> >  			      CRTC_STEREO_DOUBLE);
> >  
> > +	ret = icl_add_genlock_crtcs(crtc, pipe_config, state);
> > +	if (ret) {
> > +		DRM_DEBUG_KMS("\n8K Debug: Cannot assign genlock crtcs");
> > +		return ret;
> > +	}
> > +
> >  	/* Pass our mode to the connectors and the CRTC to give them a chance to
> >  	 * adjust it according to limitations or connector properties, and also
> >  	 * a chance to reject the mode entirely.
> 
> I thgink we should extend on this to make master/slave mode work by doing what matt roper was working on, in collaboration with Ville?
> 
> crtc->state points to drm_crtc_state, which is the uapi state, but also contains a shadow struct intel_crtc_state, which is the actual hw state. It has its own drm_crtc_state object for the real state, which gets copied after check.
> 
> This should then also be done for intel_plane_state, which will allow us to correctly handle this mode.

I don't think there's any linkage between this and the 2-pipe-1-port
cases other than we might want to handle tiled displays that way one
day to make life easier for userspace. But that has other issues such
as we'd have to generate a new EDID for the whole display from the EDIDs
of the tiles.

Also we maybe want port sync for 100% independent displays too. So IMO
no point in trying to shoehorn both things into the same bucket.

-- 
Ville Syrjälä
Intel