[Intel-gfx] [PATCH 1/4] drm/i915/tgl: Select master transcoder for MST stream

Ville Syrjälä ville.syrjala at linux.intel.com
Mon Dec 9 16:40:44 UTC 2019


On Fri, Dec 06, 2019 at 05:18:29PM -0800, José Roberto de Souza wrote:
> On TGL the blending of all the streams have moved from DDI to
> transcoder, so now every transcoder working over the same MST port must
> send its stream to a master transcoder and master will send to DDI
> respecting the time slots.
> 
> So here adding all the CRTCs that shares the same MST stream if
> needed and computing their state again, it will pick the first
> transcoder among the ones in the same stream to be master.
> 
> Most of the time skl_commit_modeset_enables() enables pipes in a
> crescent order but due DDB overlapping it might not happen, this
> scenario will be handled in the next patch.
> 
> BSpec: 50493
> BSpec: 49190
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c      |  14 +-
>  drivers/gpu/drm/i915/display/intel_display.c  |  15 +-
>  .../drm/i915/display/intel_display_types.h    |   3 +
>  drivers/gpu/drm/i915/display/intel_dp_mst.c   | 163 ++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_dp_mst.h   |   5 +
>  5 files changed, 196 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 3cacb1e279c1..be5bc506d4d3 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -1903,8 +1903,13 @@ intel_ddi_transcoder_func_reg_val_get(const struct intel_crtc_state *crtc_state)
>  		temp |= TRANS_DDI_MODE_SELECT_DP_MST;
>  		temp |= DDI_PORT_WIDTH(crtc_state->lane_count);
>  
> -		if (INTEL_GEN(dev_priv) >= 12)
> -			temp |= TRANS_DDI_MST_TRANSPORT_SELECT(crtc_state->cpu_transcoder);
> +		if (INTEL_GEN(dev_priv) >= 12) {
> +			enum transcoder master;
> +
> +			master = crtc_state->mst_master_transcoder;
> +			WARN_ON(master == INVALID_TRANSCODER);

I'd drop the WARN_ON(). If we keep adding these for every little thing
we'll drown in them.

> +			temp |= TRANS_DDI_MST_TRANSPORT_SELECT(master);
> +		}
>  	} else {
>  		temp |= TRANS_DDI_MODE_SELECT_DP_SST;
>  		temp |= DDI_PORT_WIDTH(crtc_state->lane_count);
> @@ -4372,6 +4377,11 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
>  		pipe_config->output_types |= BIT(INTEL_OUTPUT_DP_MST);
>  		pipe_config->lane_count =
>  			((temp & DDI_PORT_WIDTH_MASK) >> DDI_PORT_WIDTH_SHIFT) + 1;
> +
> +		if (INTEL_GEN(dev_priv) >= 12)
> +			pipe_config->mst_master_transcoder =
> +					REG_FIELD_GET(TRANS_DDI_MST_TRANSPORT_SELECT_MASK, temp);
> +
>  		intel_dp_get_m_n(intel_crtc, pipe_config);
>  		break;
>  	default:
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 821ba8053f9d..f89494c849ce 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -46,6 +46,7 @@
>  #include "display/intel_crt.h"
>  #include "display/intel_ddi.h"
>  #include "display/intel_dp.h"
> +#include "display/intel_dp_mst.h"
>  #include "display/intel_dsi.h"
>  #include "display/intel_dvo.h"
>  #include "display/intel_gmbus.h"
> @@ -12542,6 +12543,11 @@ static void intel_dump_pipe_config(const struct intel_crtc_state *pipe_config,
>  			      pipe_config->csc_mode, pipe_config->gamma_mode,
>  			      pipe_config->gamma_enable, pipe_config->csc_enable);
>  
> +	if (INTEL_GEN(dev_priv) >= 12 &&
> +	    intel_crtc_has_type(pipe_config, INTEL_OUTPUT_DP_MST))

Could probably print this unconditionally to keep the code less messy.

> +		DRM_DEBUG_KMS("MST master transcoder: %s\n",
> +			      transcoder_name(pipe_config->mst_master_transcoder));
> +
>  dump_planes:
>  	if (!state)
>  		return;
> @@ -13318,6 +13324,10 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>  	PIPE_CONF_CHECK_I(sync_mode_slaves_mask);
>  	PIPE_CONF_CHECK_I(master_transcoder);
>  
> +	if (INTEL_GEN(dev_priv) >= 12 &&
> +	    intel_crtc_has_type(pipe_config, INTEL_OUTPUT_DP_MST))

These checks are definitely pointless.

> +		PIPE_CONF_CHECK_I(mst_master_transcoder);
> +
>  #undef PIPE_CONF_CHECK_X
>  #undef PIPE_CONF_CHECK_I
>  #undef PIPE_CONF_CHECK_BOOL
> @@ -14406,7 +14416,7 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
>  	u32 handled = 0;
>  	int i;
>  
> -	/* Only disable port sync slaves */
> +	/* Only disable port sync and MST slaves */
>  	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
>  					    new_crtc_state, i) {
>  		if (!needs_modeset(new_crtc_state))
> @@ -14420,7 +14430,8 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
>  		 * slave CRTCs are disabled first and then master CRTC since
>  		 * Slave vblanks are masked till Master Vblanks.
>  		 */
> -		if (!is_trans_port_sync_slave(old_crtc_state))
> +		if (!is_trans_port_sync_slave(old_crtc_state) &&
> +		    !intel_dp_mst_is_slave_trans(old_crtc_state))
>  			continue;
>  
>  		intel_pre_plane_update(state, crtc);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 83ea04149b77..630a94892b7b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1054,6 +1054,9 @@ struct intel_crtc_state {
>  
>  	/* Bitmask to indicate slaves attached */
>  	u8 sync_mode_slaves_mask;
> +
> +	/* Only valid on TGL+ */
> +	enum transcoder mst_master_transcoder;
>  };
>  
>  struct intel_crtc {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 926e49f449a6..49f1518e3ab9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -87,6 +87,49 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
>  	return 0;
>  }
>  
> +/*
> + * Iterate over all the CRTCs and set mst_master_transcoder to the first active
> + * transcoder that shares the same MST connector.
> + *
> + * TODO: maybe this could be optimized to keep the old master transcoder
> + */
> +static int
> +intel_dp_mst_master_trans_compute(struct intel_encoder *encoder,
> +				  struct intel_crtc_state *pipe_config,

s/pipe_config/crtc_state/

> +				  struct drm_connector_state *conn_state)
> +{
> +	struct intel_atomic_state *state = to_intel_atomic_state(pipe_config->uapi.state);
> +	struct intel_connector *conn = to_intel_connector(conn_state->connector);

ocd: s/conn/connector/ all over.

> +	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_digital_connector_state *iter_conn_state;
> +	struct intel_connector *iter_conn;
> +	int i;
> +
> +	if (INTEL_GEN(dev_priv) < 12)
> +		return 0;
> +
> +	for_each_new_intel_connector_in_state(state, iter_conn,
> +					      iter_conn_state, i) {
> +		struct intel_crtc_state *iter_crtc_state;
> +		struct intel_crtc *iter_crtc;
> +
> +		if (conn->mst_port != iter_conn->mst_port ||
> +		    !iter_conn_state->base.crtc)
> +			continue;
> +
> +		iter_crtc = to_intel_crtc(iter_conn_state->base.crtc);
> +		iter_crtc_state = intel_atomic_get_new_crtc_state(state,
> +								  iter_crtc);
> +		if (!iter_crtc_state->uapi.active)
> +			continue;
> +
> +		pipe_config->mst_master_transcoder = iter_crtc_state->cpu_transcoder;
> +		break;

So we're going to pick this based on the connector order. How does that
fit in with the port sync, or did we not have port sync for MST yet?

To keep everything consistent and easy my idea was to pick the first
pipe as the master for both MST and port sync. 

Although I can easily imagine topologies where even that would
land us in some interesting mess. For example:
pipe A -> MST port B -> ... -> whatever : MST master
pipe B -> MST port B -> ... -> tile 0 : port sync master / MST slave
pipe C -> MST port C -> ... -> tile 1 : port sync slave / MST master
pipe D -> MST port C -> ... -> whatever : MST slave

pipe A -> MST port B -> ... -> whatever : MST master
pipe B -> MST port B -> ... -> tile 0 : port sync master / MST slave
pipe C -> MST port C -> ... -> whatever : MST master
pipe D -> MST port C -> ... -> tile 1 : port sync slave / MST slave

No idea if the hw can even do something like that. Needs more thought
if/when we enable port sync with MST (assuming we're not already doing
that).

> +	}
> +
> +	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)
> @@ -154,6 +197,98 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
>  
>  	intel_ddi_compute_min_voltage_level(dev_priv, pipe_config);
>  
> +	ret = intel_dp_mst_master_trans_compute(encoder, pipe_config,
> +						conn_state);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int
> +intel_dp_mst_atomic_master_trans_check(struct drm_connector *connector,
> +				       struct drm_atomic_state *state)

Just pass in intel_ types pls.

> +{
> +	struct drm_i915_private *dev_priv = to_i915(connector->dev);
> +	struct drm_connector_state *new_conn_state, *old_conn_state;
> +	struct drm_connector_list_iter conn_list_iter;

ocd: s/conn_list_iter/conn_iter/ 

> +	struct intel_crtc_state *intel_crtc_state;

Just 'crtc_state'

> +	struct intel_connector *intel_conn;
> +	struct drm_crtc_state *crtc_state;
> +	struct drm_connector *conn_iter;

iter_foo vs. foo_iter in this vs. the previous function. Not that I
really like that naming convention since it can get confusing with
the 'struct drm_connector_list_iter conn_iter'.

> +
> +	if (INTEL_GEN(dev_priv) < 12)
> +		return  0;
> +
> +	intel_conn = to_intel_connector(connector);
> +	new_conn_state = drm_atomic_get_new_connector_state(state, connector);
> +	old_conn_state = drm_atomic_get_old_connector_state(state, connector);

These could be done when declaring the variables.

> +
> +	if (!old_conn_state->crtc && !new_conn_state->crtc)
> +		return 0;
> +
> +	/*
> +	 * 3 cases that needs be handled here:
> +	 * - connector going from disabled to enabled:
> +	 * nothing else need to be done, drm helpers already set mode_changed in
> +	 * the CRTCs needed
> +	 * - connector going from enabled to disabled:
> +	 * if this transcoder was the master, all slaves needs a modeset
> +	 * - connector going from enabled to enabled but it needs a modeset:
> +	 * if this transcoder was the master, all slaves also needs a modeset
> +	 */

Too may special cases IMO. I suggest just blindly marking
everything on the same mst_port for modeset if this connector
needs a modeset. IIRC we have a helper for that check even...
Ah yes, intel_connector_needs_modeset().

> +
> +	/* disabled -> enabled */
> +	if (!old_conn_state->crtc && new_conn_state->crtc)
> +		return 0;
> +
> +	/* enabled -> enabled(modeset)? */
> +	if (new_conn_state->crtc) {
> +		crtc_state = drm_atomic_get_new_crtc_state(state,
> +							   new_conn_state->crtc);
> +		if (!drm_atomic_crtc_needs_modeset(crtc_state))
> +			return 0;
> +	}
> +
> +	/* handling enabled -> enabled(modeset) and enabled -> disabled */
> +	crtc_state = drm_atomic_get_old_crtc_state(state, old_conn_state->crtc);
> +	intel_crtc_state = to_intel_crtc_state(crtc_state);
> +
> +	/* If not master, nothing else needs to be handled */
> +	if (!intel_dp_mst_is_master_trans(intel_crtc_state))
> +		return 0;
> +
> +	/* It is master, add and mark all other CRTCs in the stream as changed */
> +	drm_connector_list_iter_begin(state->dev, &conn_list_iter);
> +	drm_for_each_connector_iter(conn_iter, &conn_list_iter) {
> +		struct drm_connector_state *conn_iter_state;
> +		struct intel_connector *intel_conn_iter;
> +
> +		intel_conn_iter = to_intel_connector(conn_iter);
> +		if (intel_conn_iter->mst_port != intel_conn->mst_port)
> +			continue;
> +
> +		conn_iter_state = drm_atomic_get_connector_state(state,
> +								 conn_iter);
> +		if (IS_ERR(conn_iter_state)) {
> +			drm_connector_list_iter_end(&conn_list_iter);
> +			return PTR_ERR(conn_iter_state);
> +		}
> +
> +		if (!conn_iter_state->crtc)
> +			continue;
> +
> +		crtc_state = drm_atomic_get_crtc_state(state,
> +						       conn_iter_state->crtc);
> +		if (IS_ERR(crtc_state)) {
> +			drm_connector_list_iter_end(&conn_list_iter);
> +			return PTR_ERR(conn_iter_state);
> +		}
> +
> +		crtc_state->mode_changed = true;
> +	}
> +	drm_connector_list_iter_end(&conn_list_iter);
> +
>  	return 0;
>  }
>  
> @@ -175,6 +310,10 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
>  	if (ret)
>  		return ret;
>  
> +	ret = intel_dp_mst_atomic_master_trans_check(connector, state);
> +	if (ret)
> +		return ret;
> +
>  	if (!old_conn_state->crtc)
>  		return 0;
>  
> @@ -241,6 +380,9 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
>  	intel_dp->active_mst_links--;
>  	last_mst_stream = intel_dp->active_mst_links == 0;
>  
> +	WARN_ON(INTEL_GEN(dev_priv) >= 12 && last_mst_stream &&
> +		!intel_dp_mst_is_master_trans(old_crtc_state));
> +
>  	/*
>  	 * From TGL spec: "If multi-stream slave transcoder: Configure
>  	 * Transcoder Clock Select to direct no clock to the transcoder"
> @@ -321,6 +463,9 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
>  	intel_mst->connector = connector;
>  	first_mst_stream = intel_dp->active_mst_links == 0;
>  
> +	WARN_ON(INTEL_GEN(dev_priv) >= 12 && first_mst_stream &&
> +		!intel_dp_mst_is_master_trans(pipe_config));
> +
>  	DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
>  
>  	if (first_mst_stream)
> @@ -726,3 +871,21 @@ intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port)
>  	drm_dp_mst_topology_mgr_destroy(&intel_dp->mst_mgr);
>  	/* encoders will get killed by normal cleanup */
>  }
> +
> +bool intel_dp_mst_is_master_trans(const struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> +
> +	return INTEL_GEN(dev_priv) >= 12 &&
> +	       intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST) &&
> +	       crtc_state->mst_master_transcoder == crtc_state->cpu_transcoder;

All but the last line seem redundant.

> +}
> +
> +bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> +
> +	return INTEL_GEN(dev_priv) >= 12 &&
> +	       intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST) &&
> +	       crtc_state->mst_master_transcoder != crtc_state->cpu_transcoder;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
> index f660ad80db04..e40767f78343 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
> @@ -6,10 +6,15 @@
>  #ifndef __INTEL_DP_MST_H__
>  #define __INTEL_DP_MST_H__
>  
> +#include <stdbool.h>
> +
>  struct intel_digital_port;
> +struct intel_crtc_state;
>  
>  int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
>  void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
>  int intel_dp_mst_encoder_active_links(struct intel_digital_port *intel_dig_port);
> +bool intel_dp_mst_is_master_trans(const struct intel_crtc_state *crtc_state);
> +bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state);
>  
>  #endif /* __INTEL_DP_MST_H__ */
> -- 
> 2.24.0

-- 
Ville Syrjälä
Intel


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