-----Original Message----- From: Neil Armstrong narmstrong@baylibre.com Sent: 2022年4月8日 20:40 To: Sandor Yu sandor.yu@nxp.com; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; andrzej.hajda@intel.com; robert.foss@linaro.org; Laurent.pinchart@ideasonboard.com; jonas@kwiboo.se; jernej.skrabec@gmail.com; hverkuil-cisco@xs4all.nl Cc: S.J. Wang shengjiu.wang@nxp.com; cai.huoqing@linux.dev; maxime@cerno.tech; harry.wentland@amd.com Subject: [EXT] Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for Deep Color
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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@nxp.com
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.
OK, I will add it.
val &= ~0x4;elseval |= 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).
OK.
Sandor
hdmi_modb(hdmi,HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
HDMI_VP_STUFF_PR_STUFFING_MASK,HDMI_VP_STUFF);
Thanks, Neil