From: Sandor Yu <Sandor.yu@xxxxxxx>
HDMI1.4b specification section 6.5.3:
Source shall only send GCPs with non-zero CD to sinks
that indicate support for Deep Color.
DW HDMI GCP default enabled, but only transmit CD
and do not handle AVMUTE, PP norDefault_Phase (yet).
Disable Auto GCP when 24-bit color for sinks that not support Deep Color.
Signed-off-by: Sandor Yu <Sandor.yu@xxxxxxx>
---
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 17 +++++++++++++++++
drivers/gpu/drm/bridge/synopsys/dw-hdmi.h | 3 +++
2 files changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 02d8f7e08814..312500921754 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -1108,6 +1108,8 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
unsigned int output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_PP;
struct hdmi_data_info *hdmi_data = &hdmi->hdmi_data;
u8 val, vp_conf;
+ u8 clear_gcp_auto = 0;
+
if (hdmi_bus_fmt_is_rgb(hdmi->hdmi_data.enc_out_bus_format) ||
hdmi_bus_fmt_is_yuv444(hdmi->hdmi_data.enc_out_bus_format) ||
@@ -1117,6 +1119,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
case 8:
color_depth = 4;
output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_BYPASS;
+ clear_gcp_auto = 1;
break;
case 10:
color_depth = 5;
@@ -1136,6 +1139,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
case 0:
case 8:
remap_size = HDMI_VP_REMAP_YCC422_16bit;
+ clear_gcp_auto = 1;
break;
case 10:
remap_size = HDMI_VP_REMAP_YCC422_20bit;
@@ -1160,6 +1164,19 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
HDMI_VP_PR_CD_DESIRED_PR_FACTOR_MASK);
hdmi_writeb(hdmi, val, HDMI_VP_PR_CD);
+ /* HDMI1.4b specification section 6.5.3:
+ * Source shall only send GCPs with non-zero CD to sinks
+ * that indicate support for Deep Color.
+ * GCP only transmit CD and do not handle AVMUTE, PP norDefault_Phase (yet).
+ * Disable Auto GCP when 24-bit color for sinks that not support Deep Color.
+ */
+ val = hdmi_readb(hdmi, HDMI_FC_DATAUTO3);
+ if (clear_gcp_auto == 1)
+ val &= ~HDMI_FC_DATAUTO3_GCP_AUTO;
+ else
+ val |= HDMI_FC_DATAUTO3_GCP_AUTO;
+ hdmi_writeb(hdmi, val, HDMI_FC_DATAUTO3);
+
hdmi_modb(hdmi, HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
HDMI_VP_STUFF_PR_STUFFING_MASK, HDMI_VP_STUFF);
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
index 1999db05bc3b..18df3e119553 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
@@ -850,6 +850,9 @@ enum {
HDMI_FC_DATAUTO0_VSD_MASK = 0x08,
HDMI_FC_DATAUTO0_VSD_OFFSET = 3,
+/* FC_DATAUTO3 field values */
+ HDMI_FC_DATAUTO3_GCP_AUTO = 0x04,
+
/* PHY_CONF0 field values */
HDMI_PHY_CONF0_PDZ_MASK = 0x80,
HDMI_PHY_CONF0_PDZ_OFFSET = 7,
--
2.25.1
