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

Shashank Sharma
2017-02-06T13:59:23Z

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) {
+ hdmi->scdc.supported = true;
+ if (hf_vsdb[6] & 0x40)
+ 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.
+ */
+ struct drm_hdmi_info hdmi;
};

int drm_display_info_set_bus_formats(struct drm_display_info *info,
--
1.9.1