[Intel-gfx] [PATCH 3/5] drm/i915: Remove the 8bpc shackles from DP MST

Ville Syrjälä ville.syrjala at linux.intel.com
Tue Mar 26 13:16:52 UTC 2019


On Tue, Mar 26, 2019 at 12:43:23PM +0200, Jani Nikula wrote:
> On Fri, 08 Mar 2019, Ville Syrjala <ville.syrjala at linux.intel.com> wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >
> > Allow DP MST to output any color depth. This means deep color as
> > well as falling back to 6bpc if we would otherwise require too
> > much bandwidth.
> >
> > TODO: We should probably extend bw_contstrained scheme to force
> > all streams on the link to 6bpc if we can't fit the new stream(s)
> > otherwise.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c     |   8 +-
> >  drivers/gpu/drm/i915/intel_dp_mst.c | 120 +++++++++++++++++-----------
> >  drivers/gpu/drm/i915/intel_drv.h    |   8 ++
> >  3 files changed, 83 insertions(+), 53 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index f40b3342d82a..e1ab50980b83 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1724,12 +1724,6 @@ void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
> >  	}
> >  }
> >  
> > -struct link_config_limits {
> > -	int min_clock, max_clock;
> > -	int min_lane_count, max_lane_count;
> > -	int min_bpp, max_bpp;
> > -};
> > -
> >  static bool intel_dp_source_supports_fec(struct intel_dp *intel_dp,
> >  					 const struct intel_crtc_state *pipe_config)
> >  {
> > @@ -1792,7 +1786,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
> >  }
> >  
> >  /* Adjust link config limits based on compliance test requests. */
> > -static void
> > +void
> >  intel_dp_adjust_compliance_config(struct intel_dp *intel_dp,
> >  				  struct intel_crtc_state *pipe_config,
> >  				  struct link_config_limits *limits)
> > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> > index f9ce9e87d35b..df8b396cbcdc 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > @@ -29,41 +29,81 @@
> >  #include <drm/drm_edid.h>
> >  #include <drm/drm_probe_helper.h>
> >  
> > +static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
> > +					    struct intel_crtc_state *crtc_state,
> > +					    struct drm_connector_state *conn_state,
> > +					    struct link_config_limits *limits)
> > +{
> > +	struct drm_atomic_state *state = crtc_state->base.state;
> > +	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> > +	struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > +	struct intel_connector *connector =
> > +		to_intel_connector(conn_state->connector);
> > +	const struct drm_display_mode *adjusted_mode =
> > +		&crtc_state->base.adjusted_mode;
> > +	void *port = connector->port;
> > +	bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> > +					   DP_DPCD_QUIRK_CONSTANT_N);
> > +	int slots;
> > +
> > +	for (;;) {
> 
> I'm not particularly fond of having the loop conditions sprinkled in the
> block. But looks correct.

Ah yes, we can make this a regular for loop. I was just going for
an infinite loop originally and didn't think further.

> 
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
> 
> 
> 
> > +		crtc_state->lane_count = limits->max_lane_count;
> > +		crtc_state->port_clock = limits->max_clock;
> > +		crtc_state->pipe_bpp = limits->max_bpp;
> > +
> > +		crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
> > +						       crtc_state->pipe_bpp);
> > +
> > +		slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
> > +						      port, crtc_state->pbn);
> > +		if (slots == -EDEADLK)
> > +			return slots;
> > +		if (slots >= 0)
> > +			break;
> > +
> > +		if (limits->max_bpp > limits->min_bpp) {
> > +			limits->max_bpp -= 2 * 3;
> > +			continue;
> > +		}
> > +
> > +		DRM_DEBUG_KMS("failed finding vcpi slots:%d\n", slots);
> > +
> > +		return slots;
> > +	}
> > +
> > +	intel_link_compute_m_n(crtc_state->pipe_bpp,
> > +			       crtc_state->lane_count,
> > +			       adjusted_mode->crtc_clock,
> > +			       crtc_state->port_clock,
> > +			       &crtc_state->dp_m_n,
> > +			       constant_n);
> > +	crtc_state->dp_m_n.tu = slots;
> > +
> > +	return 0;
> > +}
> > +
> >  static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  				       struct intel_crtc_state *pipe_config,
> >  				       struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> > -	struct intel_digital_port *intel_dig_port = intel_mst->primary;
> > -	struct intel_dp *intel_dp = &intel_dig_port->dp;
> > -	struct drm_connector *connector = conn_state->connector;
> > +	struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > +	struct intel_connector *connector =
> > +		to_intel_connector(conn_state->connector);
> >  	struct intel_digital_connector_state *intel_conn_state =
> >  		to_intel_digital_connector_state(conn_state);
> > -	void *port = to_intel_connector(connector)->port;
> > -	struct drm_atomic_state *state = pipe_config->base.state;
> > -	struct drm_crtc *crtc = pipe_config->base.crtc;
> > -	struct drm_crtc_state *old_crtc_state =
> > -		drm_atomic_get_old_crtc_state(state, crtc);
> > -	int bpp;
> > -	int lane_count, slots =
> > -		to_intel_crtc_state(old_crtc_state)->dp_m_n.tu;
> > -	const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> > -	int mst_pbn;
> > -	bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> > -					   DP_DPCD_QUIRK_CONSTANT_N);
> > +	const struct drm_display_mode *adjusted_mode =
> > +		&pipe_config->base.adjusted_mode;
> > +	void *port = connector->port;
> > +	struct link_config_limits limits;
> > +	int ret;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> >  		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> >  	pipe_config->has_pch_encoder = false;
> > -	bpp = 24;
> > -	if (intel_dp->compliance.test_data.bpc) {
> > -		bpp = intel_dp->compliance.test_data.bpc * 3;
> > -		DRM_DEBUG_KMS("Setting pipe bpp to %d\n",
> > -			      bpp);
> > -	}
> >  
> >  	if (intel_conn_state->force_audio == HDMI_AUDIO_AUTO)
> >  		pipe_config->has_audio =
> > @@ -76,13 +116,21 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  	 * for MST we always configure max link bw - the spec doesn't
> >  	 * seem to suggest we should do otherwise.
> >  	 */
> > -	lane_count = intel_dp_max_lane_count(intel_dp);
> > +	limits.min_clock =
> > +	limits.max_clock = intel_dp_max_link_rate(intel_dp);
> > +
> > +	limits.min_lane_count =
> > +	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> >  
> > -	pipe_config->lane_count = lane_count;
> > +	limits.min_bpp = 6 * 3;
> > +	limits.max_bpp = pipe_config->pipe_bpp;
> >  
> > -	pipe_config->pipe_bpp = bpp;
> > +	intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
> >  
> > -	pipe_config->port_clock = intel_dp_max_link_rate(intel_dp);
> > +	ret = intel_dp_mst_compute_link_config(encoder, pipe_config,
> > +					       conn_state, &limits);
> > +	if (ret)
> > +		return ret;
> >  
> >  	if (intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_AUTO) {
> >  		/*
> > @@ -99,25 +147,6 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  			intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_LIMITED;
> >  	}
> >  
> > -	mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock, bpp);
> > -	pipe_config->pbn = mst_pbn;
> > -
> > -	slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr, port,
> > -					      mst_pbn);
> > -	if (slots < 0) {
> > -		DRM_DEBUG_KMS("failed finding vcpi slots:%d\n",
> > -			      slots);
> > -		return slots;
> > -	}
> > -
> > -	intel_link_compute_m_n(bpp, lane_count,
> > -			       adjusted_mode->crtc_clock,
> > -			       pipe_config->port_clock,
> > -			       &pipe_config->dp_m_n,
> > -			       constant_n);
> > -
> > -	pipe_config->dp_m_n.tu = slots;
> > -
> >  	if (IS_GEN9_LP(dev_priv))
> >  		pipe_config->lane_lat_optim_mask =
> >  			bxt_ddi_phy_calc_lane_lat_optim_mask(pipe_config->lane_count);
> > @@ -401,7 +430,6 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
> >  	struct intel_connector *intel_connector = to_intel_connector(connector);
> >  	struct intel_dp *intel_dp = intel_connector->mst_port;
> >  	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> > -	int bpp = 24; /* MST uses fixed bpp */
> >  	int max_rate, mode_rate, max_lanes, max_link_clock;
> >  
> >  	if (drm_connector_is_unregistered(connector))
> > @@ -414,7 +442,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
> >  	max_lanes = intel_dp_max_lane_count(intel_dp);
> >  
> >  	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
> > -	mode_rate = intel_dp_link_required(mode->clock, bpp);
> > +	mode_rate = intel_dp_link_required(mode->clock, 18);
> >  
> >  	/* TODO - validate mode against available PBN for link */
> >  	if (mode->clock < 10000)
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 40ebc94b2187..fe05ed7ff749 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1904,6 +1904,14 @@ void intel_csr_ucode_suspend(struct drm_i915_private *);
> >  void intel_csr_ucode_resume(struct drm_i915_private *);
> >  
> >  /* intel_dp.c */
> > +struct link_config_limits {
> > +	int min_clock, max_clock;
> > +	int min_lane_count, max_lane_count;
> > +	int min_bpp, max_bpp;
> > +};
> > +void intel_dp_adjust_compliance_config(struct intel_dp *intel_dp,
> > +				       struct intel_crtc_state *pipe_config,
> > +				       struct link_config_limits *limits);
> >  bool intel_dp_port_enabled(struct drm_i915_private *dev_priv,
> >  			   i915_reg_t dp_reg, enum port port,
> >  			   enum pipe *pipe);
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Ville Syrjälä
Intel


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