[Intel-gfx] [PATCH 12/23] drm/i915/dp: Compute DSC pipe config in atomic check

Manasi Navare manasi.d.navare at intel.com
Tue Jul 31 02:12:52 UTC 2018


DSC params like the enable, compressed bpp, slice ocunt and
dsc_split are added to the intel_crtc_state. These parameters
are set based on the requested mode and available link parameters
during the pipe configuration in atomic check phase.
These values are then later used to populate the remaining DSC
and RC parameters before enbaling DSC in atomic commit.

v6 (From Gaurav):
* Remove function call of intel_dp_compute_dsc_params() and
invoke intel_dp_compute_dsc_params() in the patch where
it is defined to fix compilation warning (Gaurav)

v5:
Add drm_dsc_cfg in intel_crtc_state (Manasi)

v4:
* Rebase on refactoring of intel_dp_compute_config on tip (Manasi)
* Add a comment why we need to check PSR while enabling DSC (Gaurav)

v3:
* Check PPR > max_cdclock to use 2 VDSC instances (Ville)

v2:
* Add if-else for eDP/DP (Gaurav)

Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |  28 ++++---
 drivers/gpu/drm/i915/intel_display.h |   3 +-
 drivers/gpu/drm/i915/intel_dp.c      | 141 +++++++++++++++++++++++++++++++----
 drivers/gpu/drm/i915/intel_dp_mst.c  |   2 +-
 4 files changed, 146 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 577b30d..286cae2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6460,7 +6460,7 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
 
 	pipe_config->fdi_lanes = lane;
 
-	intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock,
+	intel_link_compute_m_n(pipe_config->pipe_bpp, 0, lane, fdi_dotclock,
 			       link_bw, &pipe_config->fdi_m_n, false);
 
 	ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config);
@@ -6697,21 +6697,29 @@ static void compute_m_n(unsigned int m, unsigned int n,
 }
 
 void
-intel_link_compute_m_n(int bits_per_pixel, int nlanes,
+intel_link_compute_m_n(int bits_per_pixel, uint16_t compressed_bpp,
+		       int nlanes,
 		       int pixel_clock, int link_clock,
 		       struct intel_link_m_n *m_n,
 		       bool reduce_m_n)
 {
 	m_n->tu = 64;
 
-	compute_m_n(bits_per_pixel * pixel_clock,
-		    link_clock * nlanes * 8,
-		    &m_n->gmch_m, &m_n->gmch_n,
-		    reduce_m_n);
-
-	compute_m_n(pixel_clock, link_clock,
-		    &m_n->link_m, &m_n->link_n,
-		    reduce_m_n);
+	/* For DSC, Data M/N calculation uses compressed BPP */
+	if (compressed_bpp)
+		compute_m_n(compressed_bpp * pixel_clock,
+			    link_clock * nlanes * 8,
+			    &m_n->gmch_m, &m_n->gmch_n,
+			    reduce_m_n);
+	else
+		compute_m_n(bits_per_pixel * pixel_clock,
+			    link_clock * nlanes * 8,
+			    &m_n->gmch_m, &m_n->gmch_n,
+			    reduce_m_n);
+
+		compute_m_n(pixel_clock, link_clock,
+			    &m_n->link_m, &m_n->link_n,
+			    reduce_m_n);
 }
 
 static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_display.h b/drivers/gpu/drm/i915/intel_display.h
index 0a79a46..ba013e4 100644
--- a/drivers/gpu/drm/i915/intel_display.h
+++ b/drivers/gpu/drm/i915/intel_display.h
@@ -360,7 +360,8 @@ struct intel_link_m_n {
 	     (__i)++) \
 		for_each_if(plane)
 
-void intel_link_compute_m_n(int bpp, int nlanes,
+void intel_link_compute_m_n(int bpp, uint16_t compressed_bpp,
+			    int nlanes,
 			    int pixel_clock, int link_clock,
 			    struct intel_link_m_n *m_n,
 			    bool reduce_m_n);
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c86c8f4..fb179f1 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -47,6 +47,8 @@
 
 /* DP DSC small joiner has 2 FIFOs each of 640 x 6 bytes */
 #define DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER	61440
+#define DP_DSC_MIN_SUPPORTED_BPC		8
+#define DP_DSC_MAX_SUPPORTED_BPC		10
 
 /* DP DSC throughput values used for slice count calculations KPixels/s */
 #define DP_DSC_PEAK_PIXEL_RATE			2720000
@@ -1897,6 +1899,16 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 		}
 	}
 
+	/* If DSC is supported, use the max value reported by panel */
+	if (INTEL_GEN(dev_priv) >= 10 &&
+	    drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)) {
+		bpc = min_t(u8,
+			    drm_dp_dsc_sink_max_color_depth(intel_dp->dsc_dpcd),
+			    DP_DSC_MAX_SUPPORTED_BPC);
+		if (!bpc)
+			bpp = 3*bpc;
+	}
+
 	return bpp;
 }
 
@@ -1957,14 +1969,11 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
 				link_clock = intel_dp->common_rates[clock];
 				link_avail = intel_dp_max_data_rate(link_clock,
 								    lane_count);
-
-				if (mode_rate <= link_avail) {
-					pipe_config->lane_count = lane_count;
-					pipe_config->pipe_bpp = bpp;
-					pipe_config->port_clock = link_clock;
-
+				pipe_config->lane_count = lane_count;
+				pipe_config->pipe_bpp = bpp;
+				pipe_config->port_clock = link_clock;
+				if (mode_rate <= link_avail)
 					return true;
-				}
 			}
 		}
 	}
@@ -1972,10 +1981,82 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
 	return false;
 }
 
+static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
+					struct intel_crtc_state *pipe_config,
+					struct link_config_limits *limits)
+{
+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
+	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	enum pipe pipe = to_intel_crtc(pipe_config->base.crtc)->pipe;
+	u16 dsc_max_output_bpp = 0;
+	u8 dsc_dp_slice_count = 0;
+
+	if (INTEL_GEN(dev_priv) < 10 ||
+	    !drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd))
+		return false;
+
+	/* DP DSC only supported on Pipe B and C */
+	if (pipe == PIPE_A && !intel_dp_is_edp(intel_dp))
+		return false;
+
+	/* DSC not supported for DSC sink BPC < 8 */
+	if (limits->max_bpp < 3 * DP_DSC_MIN_SUPPORTED_BPC) {
+		DRM_DEBUG_KMS("No DSC support for less than 8bpc\n");
+		return false;
+	}
+
+	if (intel_dp_is_edp(intel_dp)) {
+		pipe_config->dsc_params.compressed_bpp =
+			drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd) >> 4;
+		pipe_config->dsc_params.slice_count =
+			drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
+							true);
+	} else {
+
+		dsc_max_output_bpp = intel_dp_dsc_get_output_bpp(pipe_config->port_clock,
+								 pipe_config->lane_count,
+								 adjusted_mode->crtc_clock,
+								 adjusted_mode->crtc_hdisplay);
+		dsc_dp_slice_count = intel_dp_dsc_get_slice_count(intel_dp,
+								  adjusted_mode->crtc_clock,
+								  adjusted_mode->crtc_hdisplay);
+		if (!(dsc_max_output_bpp && dsc_dp_slice_count)) {
+			DRM_DEBUG_KMS("Compressed BPP/Slice Count not supported\n");
+			return false;
+		}
+		pipe_config->dsc_params.compressed_bpp = dsc_max_output_bpp >> 4;
+		pipe_config->dsc_params.slice_count = dsc_dp_slice_count;
+	}
+	/*
+	 * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate
+	 * is greater than the maximum Cdclock and if slice count is even
+	 * then we need to use 2 VDSC instances.
+	 */
+	pipe_config->dsc_params.dsc_split = false;
+	if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) {
+		if (pipe_config->dsc_params.slice_count > 1)
+			pipe_config->dsc_params.dsc_split = true;
+		else {
+			DRM_DEBUG_KMS("Cannot split stream to use 2 VDSC instances\n");
+			return false;
+		}
+	}
+	pipe_config->dsc_params.compression_enable = true;
+	DRM_DEBUG_KMS("DP DSC computed with Input Bpp = %d "
+		      "Compressed Bpp = %d Slice Count = %d\n",
+		      pipe_config->pipe_bpp,
+		      pipe_config->dsc_params.compressed_bpp,
+		      pipe_config->dsc_params.slice_count);
+
+	return true;
+}
+
 static bool
 intel_dp_compute_link_config(struct intel_encoder *encoder,
 			     struct intel_crtc_state *pipe_config)
 {
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
 	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
 	struct link_config_limits limits;
@@ -1993,7 +2074,9 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 	limits.min_lane_count = 1;
 	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
 
-	limits.min_bpp = 6 * 3;
+	limits.min_bpp = (INTEL_GEN(dev_priv) >= 10 &&
+			  drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)) ?
+		DP_DSC_MIN_SUPPORTED_BPC * 3 : 6 * 3;
 	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
 
 	if (intel_dp_is_edp(intel_dp)) {
@@ -2020,19 +2103,43 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 	 * Optimize for slow and wide. This is the place to add alternative
 	 * optimization policy.
 	 */
-	if (!intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits))
-		return false;
+	if (!intel_dp_compute_link_config_wide(intel_dp, pipe_config,
+					       &limits)) {
 
-	DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
-		      pipe_config->lane_count, pipe_config->port_clock,
-		      pipe_config->pipe_bpp);
+		DRM_DEBUG_KMS("DP required Link rate %i does not fit available %i\n",
+			      intel_dp_link_required(adjusted_mode->crtc_clock,
+						     pipe_config->pipe_bpp),
+			      intel_dp_max_data_rate(pipe_config->port_clock,
+						     pipe_config->lane_count));
+
+		/* enable compression if the mode doesn't fit available BW */
+		if (!intel_dp_dsc_compute_config(intel_dp, pipe_config,
+						 &limits))
+			return false;
+	}
+
+	if (pipe_config->dsc_params.compression_enable) {
+		DRM_DEBUG_KMS("DP lane count %d clock %d Input bpp %d Compressed bpp %d\n",
+			      pipe_config->lane_count, pipe_config->port_clock,
+			      pipe_config->pipe_bpp,
+			      pipe_config->dsc_params.compressed_bpp);
 
 	DRM_DEBUG_KMS("DP link rate required %i available %i\n",
 		      intel_dp_link_required(adjusted_mode->crtc_clock,
-					     pipe_config->pipe_bpp),
+					     pipe_config->dsc_params.compressed_bpp),
 		      intel_dp_max_data_rate(pipe_config->port_clock,
 					     pipe_config->lane_count));
+	} else {
+		DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
+			      pipe_config->lane_count, pipe_config->port_clock,
+			      pipe_config->pipe_bpp);
 
+	DRM_DEBUG_KMS("DP link rate required %i available %i\n",
+		      intel_dp_link_required(adjusted_mode->crtc_clock,
+					     pipe_config->pipe_bpp),
+		      intel_dp_max_data_rate(pipe_config->port_clock,
+					     pipe_config->lane_count));
+	}
 	return true;
 }
 
@@ -2111,7 +2218,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 			intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_LIMITED;
 	}
 
-	intel_link_compute_m_n(pipe_config->pipe_bpp, pipe_config->lane_count,
+	intel_link_compute_m_n(pipe_config->pipe_bpp,
+			       pipe_config->dsc_params.compressed_bpp,
+			       pipe_config->lane_count,
 			       adjusted_mode->crtc_clock,
 			       pipe_config->port_clock,
 			       &pipe_config->dp_m_n,
@@ -2120,7 +2229,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	if (intel_connector->panel.downclock_mode != NULL &&
 		dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
 			pipe_config->has_drrs = true;
-			intel_link_compute_m_n(pipe_config->pipe_bpp,
+			intel_link_compute_m_n(pipe_config->pipe_bpp, 0,
 					       pipe_config->lane_count,
 					       intel_connector->panel.downclock_mode->clock,
 					       pipe_config->port_clock,
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 352e521..4f941b8 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -83,7 +83,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 		return false;
 	}
 
-	intel_link_compute_m_n(bpp, lane_count,
+	intel_link_compute_m_n(bpp, 0, lane_count,
 			       adjusted_mode->crtc_clock,
 			       pipe_config->port_clock,
 			       &pipe_config->dp_m_n,
-- 
2.7.4



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