HDMI 2.0 spec adds support for ycbcr420 subsampled output.
CEA-861-F adds two new blocks in EDID, to provide information about
sink's support for ycbcr420 output.
One of these new blocks is: ycbcr420 vcb
- ycbcr420 video capability data (vcb) block: video modes which can be
support in ycbcr420 output mode also (along with RGB, YCBCR 444/422 etc)
This patch adds parsing and handling of ycbcr420-vcb in the DRM layer.
This block contains a bitmap about which mode, from among the list of
normal svd videomodes, can support ycbcr420 output too.
So if bit 0 from first vcb byte is set, means first video mode in the
svd list, can be supported in ycbcr420 output too. Bit 2 means second
video mode from svd list, and so on.
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Jose Abreu <joabreu@xxxxxxxxxxxx>
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 80 +++++++++++++++++++++++++++++++++++++++++++--
include/drm/drm_connector.h | 1 +
2 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 64d8e2e..d01b7df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2778,6 +2778,7 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
#define SPEAKER_BLOCK 0x04
#define VIDEO_CAPABILITY_BLOCK 0x07
#define VIDEO_DATA_BLOCK_420 0x0E
+#define VIDEO_CAP_BLOCK_420 0x0F
#define EDID_BASIC_AUDIO (1 << 6)
#define EDID_CEA_YCRCB444 (1 << 5)
#define EDID_CEA_YCRCB422 (1 << 4)
@@ -3143,11 +3144,21 @@ static int
do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len)
{
int i, modes = 0;
+ u64 hdmi_420_cap_map = connector->display_info.hdmi.ycbcr420_vcb_map;
for (i = 0; i < len; i++) {
struct drm_display_mode *mode;
mode = drm_display_mode_from_vic_index(connector, db, len, i);
if (mode) {
+ /*
+ * ycbcr420 capability block contains a bitmap which
+ * gives the index of such CEA modes in VDB, which can
+ * support ycbcr420 sampling output also.
+ * For example, if the bit 0 in bitmap is set,
+ * first mode in VDB can support ycbcr420 output too.
+ */
+ if (hdmi_420_cap_map & (1 << i))
+ mode->flags |= DRM_MODE_FLAG_420;
drm_mode_probed_add(connector, mode);
modes++;
}
@@ -3526,9 +3537,64 @@ static bool cea_db_is_hdmi_vdb420(const u8 *db)
return true;
}
+static bool cea_db_is_hdmi_vcb420(const u8 *db)
+{
+ if (cea_db_tag(db) != VIDEO_CAPABILITY_BLOCK)
+ return false;
+
+ if (cea_db_extended_tag(db) != VIDEO_CAP_BLOCK_420)
+ return false;
+
+ return true;
+}
+
#define for_each_cea_db(cea, i, start, end) \
for ((i) = (start); (i) < (end) && (i) + cea_db_payload_len(&(cea)[(i)]) < (end); (i) += cea_db_payload_len(&(cea)[(i)]) + 1)
+static void drm_parse_vcb_420_bitmap(struct drm_connector *connector,
+ const u8 *db)
+{
+ struct drm_display_info *info = &connector->display_info;
+ struct drm_hdmi_info *hdmi = &info->hdmi;
+ u8 map_len = cea_db_payload_len(db) - 1;
+ u8 count;
+ u64 map = 0;
+
+ if (!db)
+ return;
+
+ if (map_len == 0) {
+ /* All CEA modes support ycbcr420 sampling also.*/
+ hdmi->ycbcr420_vcb_map = U64_MAX;
+ return;
+ }
+
+ /*
+ * This map indicates which of the existing CEA block modes
+ * from VDB can support YCBCR420 output too. So if bit=0 is
+ * set, first mode from VDB can support YCBCR420 output too.
+ * We will parse and keep this map, before parsing VDB itself
+ * to avoid going through the same block again and again.
+ *
+ * Spec is not clear about max possible size of this block.
+ * Clamping max bitmap block size at 8 bytes. Every byte can
+ * address 8 CEA modes, in this way this map can address
+ * 8*8 = first 64 SVDs.
+ */
+ if (map_len > 8)
+ map_len = 8;
+
+ for (count = 0; count < map_len; count++)
+ map = (db[2 + count] << 8 * count) | map;
+
+ if (map) {
+ DRM_DEBUG_KMS("Sink supports ycbcr 420\n");
+ info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
+ }
+
+ hdmi->ycbcr420_vcb_map = map;
+}
+
static int
add_cea_modes(struct drm_connector *connector, struct edid *edid)
{
@@ -3561,6 +3627,8 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
/* Add 4:2:0(only) modes present in EDID */
modes += do_420_vdb_modes(connector, vdb420,
vdb420_len);
+ } else if (cea_db_is_hdmi_vcb420(db)) {
+ drm_parse_vcb_420_bitmap(connector, db);
}
}
}
@@ -4241,6 +4309,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
drm_parse_hdmi_vsdb_video(connector, db);
if (cea_db_is_hdmi_forum_vsdb(db))
drm_parse_hdmi_forum_vsdb(connector, db);
+ if (cea_db_is_hdmi_vcb420(db))
+ drm_parse_vcb_420_bitmap(connector, db);
}
}
@@ -4492,6 +4562,14 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
num_modes += add_cvt_modes(connector, edid);
num_modes += add_standard_modes(connector, edid);
num_modes += add_established_modes(connector, edid);
+
+ /*
+ * CEA-861-F adds ycbcr capability map block, for HDMI 2.0 sinks.
+ * To avoid multiple parsing of same block, lets get the sink info
+ * before parsing CEA modes.
+ */
+ drm_add_display_info(connector, edid);
+
num_modes += add_cea_modes(connector, edid);
num_modes += add_alternate_cea_modes(connector, edid);
num_modes += add_displayid_detailed_modes(connector, edid);
@@ -4501,8 +4579,6 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
edid_fixup_preferred(connector, quirks);
- drm_add_display_info(connector, edid);
-
if (quirks & EDID_QUIRK_FORCE_6BPC)
connector->display_info.bpc = 6;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index cef76b2..dbfa6a1 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -136,6 +136,7 @@ struct drm_scdc {
struct drm_hdmi_info {
/** @scdc: sink's scdc support and capabilities */
struct drm_scdc scdc;
+ u64 ycbcr420_vcb_map;
};
/**
--
2.7.4
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