2022-04-08 12:33:09

by Sandor Yu

Subject: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for Deep Color

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.

Signed-off-by: Sandor Yu <[email protected]>
---
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 */
+ val &= ~0x4;
+ else
+ val |= 0x4;
+ 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);

--
2.25.1

2022-04-08 16:34:58

by Neil Armstrong

Subject: Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for Deep Color

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 <[email protected]>
> ---
> 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

2022-04-12 22:57:40

by Sandor Yu

Subject: RE: [EXT] Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for Deep Color

> -----Original Message-----
> From: Neil Armstrong <[email protected]>
> Sent: 2022年4月8日 20:40
> To: Sandor Yu <[email protected]>; [email protected];
> [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]
> Cc: S.J. Wang <[email protected]>; [email protected];
> [email protected]; [email protected]
> Subject: [EXT] Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for
> Deep Color
>
> Caution: EXT Email
>
> 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 <[email protected]>
> > ---
> > 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;
> > + 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).
>
OK.

Sandor
> > +
> > hdmi_modb(hdmi,
> HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
> > HDMI_VP_STUFF_PR_STUFFING_MASK,
> HDMI_VP_STUFF);
> >
>
> Thanks,
> Neil