HDMI 2.0 spec adds support for ycbcr420 sub-sampled 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: ycbcr420cmdb(ycbcr 420 capability
map data block). This gives information about video modes which
can support ycbcr420 output mode also (along with RGB,YCBCR444/
422 etc)
This block contains a bitmap index of normal svd videomodes, which can
support ycbcr420 output too.
So if bit 0 from first vcb byte is set,first video mode in the svd list
can support ycbcr420 output too. Bit 2 means second video mode from svd
list can support ycbcr420 output too, and so on.
This patch adds parsing and handling of ycbcr420-cmdb in the DRM layer.
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: Emil Velikov <emil.l.velikov@xxxxxxxxx>
V2: Addressed
Review comments from Emil:
- Use 1ULL<<i instead of 1<<i to make sure the output is 64bit.
- Use the suggested method for updating dbmap.
- Add documentation for ycbcr420_vcb_map to fix kbuild warning.
Review comments from Ville:
- Do not expose the ycbcr420 flags in uabi layer, keep it internal.
- Save a map of ycbcr420 modes for future reference.
- Check db length before trying to parse extended tag.
- Add a warning if there are > 64 modes in capability map block.
- Use y420cmdb in function names and macros while dealing with vcb
to be aligned with spec.
- Move the display information parsing block ahead of mode parsing
blocks.
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 118 ++++++++++++++++++++++++++++++++++++++++++--
include/drm/drm_connector.h | 12 +++++
2 files changed, 127 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index c3fa3a1..ce86528 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2781,7 +2781,9 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
#define VIDEO_BLOCK 0x02
#define VENDOR_BLOCK 0x03
#define SPEAKER_BLOCK 0x04
-#define VIDEO_CAPABILITY_BLOCK 0x07
+#define VIDEO_CAPABILITY_BLOCK 0x07
+#define VIDEO_DATA_BLOCK_420 0x0E
+#define VIDEO_CAP_BLOCK_Y420CMDB 0x0F
#define EDID_BASIC_AUDIO (1 << 6)
#define EDID_CEA_YCRCB444 (1 << 5)
#define EDID_CEA_YCRCB422 (1 << 4)
@@ -3143,15 +3145,50 @@ drm_display_mode_from_vic_index(struct drm_connector *connector,
return newmode;
}
+static void
+drm_add_vcb_modes(struct drm_connector *connector, u8 vic)
+{
+ u32 *map;
+ u8 index = 0;
+ struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+
+ /* VICs are 1 to 127(107 defined till CEA-861-F) */
+ vic &= 127;
+
+ /*
+ * ycbcr420_vcb_modes is a fix position 128 bit bitmap. This indicates
+ * support for ycbcr420 output per VIC. Arrangement is bit[n] indicates
+ * if vic[n+1] supports ycbcr420 output.
+ * ycbcr420_vcb_modes[0] = |VIC=32 |VIC=31 |............|VIC=2 |VIC=1 |
+ * ycbcr420_vcb_modes[1] = |VIC=64 |VIC=63 |............|VIC=34|VIC=33|
+ * ycbcr420_vcb_modes[2] = |VIC=96 |VIC=95 |............|VIC=66|VIC=65|
+ * ycbcr420_vcb_modes[3] = |VIC=128|VIC=127|............|VIC=34|VIC=97|
+ */
+ map = &(hdmi->ycbcr420_vcb_modes[(vic - 1) / 32]);
+ index = (vic - 1) % 32;
+ *map |= (1 << index);
+}
+
static int
do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len)
{
int i, modes = 0;
+ struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+ u64 hdmi_vcb_map = 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_vcb_map & (1 << i))
+ drm_add_vcb_modes(connector, db[i]);
drm_mode_probed_add(connector, mode);
modes++;
}
@@ -3427,6 +3464,12 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len,
}
static int
+cea_db_extended_tag(const u8 *db)
+{
+ return db[1];
+}
+
+static int
cea_db_payload_len(const u8 *db)
{
return db[0] & 0x1f;
@@ -3487,9 +3530,70 @@ static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)
return oui == HDMI_FORUM_IEEE_OUI;
}
+static bool cea_db_is_y420cmdb(const u8 *db)
+{
+ u8 len = cea_db_payload_len(db);
+
+ if (cea_db_tag(db) != VIDEO_CAPABILITY_BLOCK)
+ return false;
+
+ if (!len)
+ return false;
+
+ if (cea_db_extended_tag(db) != VIDEO_CAP_BLOCK_Y420CMDB)
+ 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_y420cmdb_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;
+ info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
+ 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 (WARN_ON_ONCE(map_len > 8))
+ map_len = 8;
+
+ for (count = 0; count < map_len; count++)
+ map |= (u64)db[2 + count] << (8 * count);
+
+ 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)
{
@@ -4196,6 +4300,8 @@ 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_y420cmdb(db))
+ drm_parse_y420cmdb_bitmap(connector, db);
}
}
@@ -4430,6 +4536,13 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
quirks = edid_get_quirks(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);
+
+ /*
* EDID spec says modes should be preferred in this order:
* - preferred detailed mode
* - other detailed modes from base block
@@ -4450,14 +4563,13 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
num_modes += add_cea_modes(connector, edid);
num_modes += add_alternate_cea_modes(connector, edid);
num_modes += add_displayid_detailed_modes(connector, edid);
+
if (edid->features & DRM_EDID_FEATURE_DEFAULT_GTF)
num_modes += add_inferred_modes(connector, 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 2fe09c1..07b10ab 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -137,6 +137,17 @@ struct drm_scdc {
struct drm_hdmi_info {
/** @scdc: sink's scdc support and capabilities */
struct drm_scdc scdc;
+
+ /**
+ * @ycbcr420_vcb_modes: bitmap of modes which can support ycbcr420
+ * output also along with normal outputs. There are total 107 VICs
+ * defined by CEA-861-F spec, so the size is 128bits to map upto 128
+ * VICs;
+ */
+ u32 ycbcr420_vcb_modes[4];
+
+ /** @ycbcr420_vcb_map: bitmap of SVD index, to extraxt vcb modes */
+ u64 ycbcr420_vcb_map;
};
/**
@@ -200,6 +211,7 @@ struct drm_display_info {
#define DRM_COLOR_FORMAT_RGB444 (1<<0)
#define DRM_COLOR_FORMAT_YCRCB444 (1<<1)
#define DRM_COLOR_FORMAT_YCRCB422 (1<<2)
+#define DRM_COLOR_FORMAT_YCRCB420 (1<<3)
/**
* @color_formats: HDMI Color formats, selects between RGB and YCrCb
--
2.7.4
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