[Intel-gfx] [PATCH 3/5] Add support for forcing 6 bpc on DP pipes.

[Manasi Navare]

From: Jim Bride <jim.bride at linux.intel.com>

For DP compliance we need to be able to control the output color
type for the pipe associated with the DP port. When a specific DP
compliance test is requested with specific BPC value, we read the BPC
value from the DPCD register and store it in the intel_dp structure.
If this BPC value in intel_dp structure  has a non-zero value
and we're on a display port connector, then we use the value to
calculate the bpp for the pipe.  For cases where we are
not on DP or there has not been an overridden value then we behave
as normal.

Signed-off-by: Jim Bride <jim.bride at linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |  4 +++-
 drivers/gpu/drm/i915/intel_dp.c      | 10 ++++++++++
 drivers/gpu/drm/i915/intel_dp_mst.c  | 11 +++++++++--
 drivers/gpu/drm/i915/intel_drv.h     |  1 +
 4 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b7a7ed8..bb1cca2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12694,11 +12694,13 @@ static void intel_modeset_update_connector_atomic_state(struct drm_device *dev)
 
 	/* Clamp display bpp to EDID value */
 	for_each_connector_in_state(state, connector, connector_state, i) {
+
 		if (connector_state->crtc != &crtc->base)
 			continue;
 
 		connected_sink_compute_bpp(to_intel_connector(connector),
-					   pipe_config);
+						   pipe_config);
+
 	}
 
 	return bpp;
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 6693918..f93e130 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1549,6 +1549,13 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	if (bpc > 0)
 		bpp = min(bpp, 3*bpc);
 
+	/* For DP Compliance we override the computed bpp for the pipe */
+	if (intel_dp->compliance_force_bpc != 0) {
+		pipe_config->pipe_bpp =	intel_dp->compliance_force_bpc*3;
+		DRM_DEBUG_KMS("Setting pipe_bpp to %d\n",
+			      pipe_config->pipe_bpp);
+	}
+
 	return bpp;
 }
 
@@ -1629,6 +1636,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	/* Walk through all bpp values. Luckily they're all nicely spaced with 2
 	 * bpc in between. */
 	bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
+
 	if (is_edp(intel_dp)) {
 
 		/* Get bpp from vbt only for panels that dont have bpp in edid */
@@ -4109,6 +4117,7 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
 	intel_dp->compliance_test_data = 0;
 	intel_dp->compliance_test_lane_count = 0;
 	intel_dp->compliance_test_link_rate = 0;
+	intel_dp->compliance_force_bpc = 0;
 
 	/*
 	 * Now read the DPCD to see if it's actually running
@@ -4434,6 +4443,7 @@ static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
 		intel_dp->compliance_test_active = 0;
 		intel_dp->compliance_test_type = 0;
 		intel_dp->compliance_test_data = 0;
+		intel_dp->compliance_force_bpc = 0;
 		intel_dp->compliance_test_lane_count = 0;
 		intel_dp->compliance_test_link_rate = 0;
 
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index b029d10..940f173 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -45,6 +45,14 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 
 	pipe_config->has_pch_encoder = false;
 	bpp = 24;
+	/* For DP Compliance we need to ensurethat we can override
+	 * the computed bpp for the pipe
+	 */
+	if (intel_dp->compliance_force_bpc) {
+		bpp = intel_dp->compliance_force_bpc * 3;
+		DRM_DEBUG_KMS("Setting pipe bpp to %d\n",
+			      bpp);
+	}
 	/*
 	 * for MST we always configure max link bw - the spec doesn't
 	 * seem to suggest we should do otherwise.
@@ -52,8 +60,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 	lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
 
 	pipe_config->lane_count = lane_count;
-
-	pipe_config->pipe_bpp = 24;
+	pipe_config->pipe_bpp = bpp;
 	pipe_config->port_clock = intel_dp_max_link_rate(intel_dp);
 
 	state = pipe_config->base.state;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1e88288..3eb428e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -960,6 +960,7 @@ struct intel_dp {
 	bool compliance_test_active;
 	u8 compliance_test_lane_count;
 	u8 compliance_test_link_rate;
+	unsigned long compliance_force_bpc; /* 0 for default or bpc to use */
 };
 
 struct intel_lspcon {
-- 
1.9.1