Re: [PATCH v2 3/6] drm/edid: detect SCDC support in HF-VSDB

Jose Abreu
2017-02-07T11:01:19Z

Hi Shashank,

On 06-02-2017 13:59, Shashank Sharma wrote:
> This patch does following:
> - Adds a new structure (drm_hdmi_info) in drm_display_info.
> This structure will be used to save and indicate if sink
> supports advanced HDMI 2.0 features
> - Adds another structure drm_scdc within drm_hdmi_info, to
> reflect scdc support and capabilities in connected HDMI 2.0 sink.
> - Checks the HF-VSDB block for presence of SCDC, and marks it
> in scdc structure
> - If SCDC is present, checks if sink is capable of generating
> SCDC read request, and marks it in scdc structure.
>
> V2: Addressed review comments
> Thierry:
> - Fix typos in commit message and make abbreviation consistent
> across the commit message.
> - Change structure object name from hdmi_info -> hdmi
> - Fix typos and abbreviations in description of structure drm_hdmi_info
> end the description with a full stop.
> - Create a structure drm_scdc, and keep all information related to SCDC
> register set (supported, read request supported) etc in it.
>
> Ville:
> - Change rr -> read_request
> - Call drm_detect_scrambling function drm_parse_hf_vsdb so that all
> of HF-VSDB parsing can be kept in same function, in incremental
> patches.
>
> Reviewed-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
> drivers/gpu/drm/drm_edid.c | 14 ++++++++++++++
> include/drm/drm_connector.h | 33 +++++++++++++++++++++++++++++++++
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 96d3e47..a487b80 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3802,6 +3802,18 @@ enum hdmi_quantization_range
> }
> EXPORT_SYMBOL(drm_default_rgb_quant_range);
>
> +static void drm_parse_hdmi_forum_vsdb(struct drm_connector *connector,
> + const u8 *hf_vsdb)
> +{
> + struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
> +
> + if (hf_vsdb[6] & 0x80) {

BIT(7) ?

> + hdmi->scdc.supported = true;
> + if (hf_vsdb[6] & 0x40)

BIT(6) ?

> + hdmi->scdc.read_request = true;
> + }
> +}
> +
> static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
> const u8 *hdmi)
> {
> @@ -3916,6 +3928,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
>
> if (cea_db_is_hdmi_vsdb(db))
> drm_parse_hdmi_vsdb_video(connector, db);
> + if (cea_db_is_hdmi_forum_vsdb(db))
> + drm_parse_hdmi_forum_vsdb(connector, db);
> }
> }
>
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index e5e1edd..6d5304e 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -87,6 +87,34 @@ enum subpixel_order {
> SubPixelVerticalRGB,
> SubPixelVerticalBGR,
> SubPixelNone,
> +
> +};
> +
> +/*
> + * struct drm_scdc - Information about scdc capabilities of a HDMI 2.0 sink
> + *
> + * Provides SCDC register support and capabilities related information on a
> + * HDMI 2.0 sink. In case of a HDMI 1.4 sink, all parameter must be 0.
> + */
> +struct drm_scdc {
> + /**
> + * @supported: status control & data channel present.
> + */
> + bool supported;
> + /**
> + * @read_request: sink is capable of generating scdc read request.
> + */
> + bool read_request;
> +};
> +
> +/**
> + * struct drm_hdmi_info - runtime information about the connected HDMI sink
> + *
> + * Describes if a given display supports advanced HDMI 2.0 features.
> + * This information is available in CEA-861-F extension blocks (like HF-VSDB).
> + */
> +struct drm_hdmi_info {
> + struct drm_scdc scdc;
> };
>
> /**
> @@ -188,6 +216,11 @@ struct drm_display_info {
> * @cea_rev: CEA revision of the HDMI sink.
> */
> u8 cea_rev;
> +
> + /**
> + * @hdmi: advance features of a HDMI sink.

Maybe change to the same general description you used above:
"Runtime information about the connected HDMI sink" ?

> + */
> + struct drm_hdmi_info hdmi;
> };
>
> int drm_display_info_set_bus_formats(struct drm_display_info *info,

Best regards,
Jose Miguel Abreu