[Intel-gfx] [PATCH v3] drm/i915/icl: Set GCP_COLOR_INDICATION only for 10/12 bit deep color

[Aditya Swarup]

From: Clinton Taylor <Clinton.A.Taylor at intel.com>

v2: Fix commit msg to reflect why issue occurs(Jani)
Set GCP_COLOR_INDICATION only when we set 10/12 bit deep color.

Changing settings from 10/12 bit deep color to 8 bit(& vice versa)
doesn't work correctly using xrandr max bpc property. When we
connect a monitor which supports deep color, the highest deep color
setting is selected; which sets GCP_COLOR_INDICATION. When we change
the setting to 8 bit color, we still set GCP_COLOR_INDICATION which
doesn't allow the switch back to 8 bit color.

v3: Add comments & explain changes in intel_hdmi_compute_config(Ville)
Since HSW+, GCP_COLOR_INDICATION is not required for 8bpc.

Also, remove unnecessary calls to hdmi_deep_color_possible() from
intel_hdmi_compute_config()

Ideally, hdmi_deep_color_possible() should be called only
once to determine whether it is possible to set 10 or 12 bit
deep color mode and adjust the desired bpp based on pipe_bpp
instead of hard coding the values.

Signed-off-by: Clinton Taylor <Clinton.A.Taylor at intel.com>
Signed-off-by: Aditya Swarup <aditya.swarup at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/i915/intel_hdmi.c | 36 ++++++++++++++++---------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 5ccb305a6e1c..a93736fb1950 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -962,8 +962,13 @@ static void intel_hdmi_compute_gcp_infoframe(struct intel_encoder *encoder,
 	crtc_state->infoframes.enable |=
 		intel_hdmi_infoframe_enable(HDMI_PACKET_TYPE_GENERAL_CONTROL);
 
-	/* Indicate color depth whenever the sink supports deep color */
-	if (hdmi_sink_is_deep_color(conn_state))
+	/* Indicate color depth whenever the sink supports deep color.
+	 * Also, 8bpc + color depth indication is no longer supported
+	 * for HSW+ platforms.
+	 * */
+
+	if (hdmi_sink_is_deep_color(conn_state) &&
+	    crtc_state->pipe_bpp > 24)
 		crtc_state->infoframes.gcp |= GCP_COLOR_INDICATION;
 
 	/* Enable default_phase whenever the display mode is suitably aligned */
@@ -2260,6 +2265,7 @@ int intel_hdmi_compute_config(struct intel_encoder *encoder,
 	int clock_8bpc = pipe_config->base.adjusted_mode.crtc_clock;
 	int clock_10bpc = clock_8bpc * 5 / 4;
 	int clock_12bpc = clock_8bpc * 3 / 2;
+	int dc_clock = clock_12bpc;
 	int desired_bpp;
 	bool force_dvi = intel_conn_state->force_audio == HDMI_AUDIO_OFF_DVI;
 
@@ -2314,22 +2320,18 @@ int intel_hdmi_compute_config(struct intel_encoder *encoder,
 	 * Note that g4x/vlv don't support 12bpc hdmi outputs. We also need
 	 * to check that the higher clock still fits within limits.
 	 */
-	if (hdmi_deep_color_possible(pipe_config, 12) &&
-	    hdmi_port_clock_valid(intel_hdmi, clock_12bpc,
+	if (pipe_config->pipe_bpp == 30)
+		dc_clock = clock_10bpc;
+
+	if (hdmi_deep_color_possible(pipe_config, pipe_config->pipe_bpp / 3) &&
+	    hdmi_port_clock_valid(intel_hdmi, dc_clock,
 				  true, force_dvi) == MODE_OK) {
-		DRM_DEBUG_KMS("picking bpc to 12 for HDMI output\n");
-		desired_bpp = 12*3;
-
-		/* Need to adjust the port link by 1.5x for 12bpc. */
-		pipe_config->port_clock = clock_12bpc;
-	} else if (hdmi_deep_color_possible(pipe_config, 10) &&
-		   hdmi_port_clock_valid(intel_hdmi, clock_10bpc,
-					 true, force_dvi) == MODE_OK) {
-		DRM_DEBUG_KMS("picking bpc to 10 for HDMI output\n");
-		desired_bpp = 10 * 3;
-
-		/* Need to adjust the port link by 1.25x for 10bpc. */
-		pipe_config->port_clock = clock_10bpc;
+		DRM_DEBUG_KMS("picking bpc to %d for HDMI output\n",
+			       pipe_config->pipe_bpp / 3);
+		desired_bpp = pipe_config->pipe_bpp;
+
+		/* Need to adjust the port link dc modes. */
+		pipe_config->port_clock = dc_clock;
 	} else {
 		DRM_DEBUG_KMS("picking bpc to 8 for HDMI output\n");
 		desired_bpp = 8*3;
-- 
2.17.1