[Intel-gfx] [PATCH 4/5] 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. To do this we rely
on the intel_dp_test_force_bpc debugfs file and the associated value
stored in struct intel_dp. If the debugfs file has a non-zero value
and we're on a display port connector, then we use the value from
debugfs 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>
---
 drivers/gpu/drm/i915/intel_display.c | 32 ++++++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/intel_drv.h     |  1 +
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5ffccf6..1618d36 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12102,11 +12102,39 @@ compute_baseline_pipe_bpp(struct intel_crtc *crtc,
 
 	/* Clamp display bpp to EDID value */
 	for_each_connector_in_state(state, connector, connector_state, i) {
+		int type = 0;
+
+		if (connector_state->best_encoder) {
+			struct intel_encoder *ienc;
+
+			ienc = to_intel_encoder(connector_state->best_encoder);
+			type = ienc->type;
+		}
+
 		if (connector_state->crtc != &crtc->base)
 			continue;
 
-		connected_sink_compute_bpp(to_intel_connector(connector),
-					   pipe_config);
+		/* For DP compliance we need to ensure that we can override
+		 * the computed bpp for the pipe.
+		 */
+		if (type == INTEL_OUTPUT_DISPLAYPORT) {
+			struct intel_dp *intel_dp =
+				enc_to_intel_dp(connector_state->best_encoder);
+
+			if (intel_dp &&
+			    (intel_dp->compliance_force_bpc != 0)) {
+				pipe_config->pipe_bpp =
+					intel_dp->compliance_force_bpc*3;
+				DRM_DEBUG_KMS("JMB Setting pipe_bpp to %d\n",
+					      pipe_config->pipe_bpp);
+			} else {
+				connected_sink_compute_bpp(to_intel_connector(connector),
+						   pipe_config);
+			}
+		} else {
+			connected_sink_compute_bpp(to_intel_connector(connector),
+						   pipe_config);
+		}
 	}
 
 	return bpp;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index e23eed7..10eaff8 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -865,6 +865,7 @@ struct intel_dp {
 	unsigned long compliance_test_type;
 	unsigned long compliance_test_data;
 	bool compliance_test_active;
+	unsigned long compliance_force_bpc; /* 0 for default or bpc to use */
 };
 
 struct intel_digital_port {
-- 
1.9.1