On 08/04/2022 12:32, Sandor Yu wrote:
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, clear gpc_auto bit for 24-bit color depth.
It's right because we do not handle AVMUTE, Pixel Packing nor Default_Phase.
Signed-off-by: Sandor Yu <Sandor.yu@xxxxxxx>
---
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 02d8f7e08814..5a7ec066e37a 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 +1164,14 @@ 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);
+ val = hdmi_readb(hdmi, HDMI_FC_DATAUTO3);
+ if (clear_gcp_auto == 1)
+ /* disable Auto GCP when 24-bit color */
Maybe add a new define for HDMI_FC_DATAUTO3_GCP_AUTO bit and use it here.
+ val &= ~0x4;
+ else
+ val |= 0x4;
+ hdmi_writeb(hdmi, val, HDMI_FC_DATAUTO3);
Please also add a comment explaining we clear GCP because we only
transmit CD and do not handle AVMUTE, PP nor Default_Phase (yet).
+
hdmi_modb(hdmi, HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
HDMI_VP_STUFF_PR_STUFFING_MASK, HDMI_VP_STUFF);
Thanks,
Neil
