HDMI 2.0 spec adds support for YCBCR420 sub-sampled output.
CEA-861-F adds two new blocks in EDID's CEA extension blocks,
to provide information about sink's YCBCR420 output capabilities.
These blocks are:
- YCBCR420vdb(YCBCR 420 video data block):
This block contains VICs of video modes, which can be sopported only
in YCBCR420 output mode (Not in RGB/YCBCR444/422. Its like a normal
SVD block, valid for YCBCR420 modes only.
- YCBCR420cmdb(YCBCR 420 capability map data block):
This block 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 1 means second video mode
from svd list can support YCBCR420 output too, and so on.
This patch adds two bitmaps in display's hdmi_info structure, one each
for VCB and VDB modes. If the source is HDMI 2.0 capable, this patch
adds:
- VDB modes (YCBCR 420 only modes) in connector's mode list, also makes
an entry in the vdb_bitmap per vic.
- VCB modes (YCBCR 420 also modes) only entry in the vcb_bitmap.
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.
V3: Addressed design/review comments from Ville
- Do not add flags in video modes, else we have to expose them to user
- There should not be a UABI change, and kernel should detect the
choice of the output based on type of mode, and the bitmaps.
- Use standard bitops from kernel bitmap header, instead of calculating
bit positions manually.
V4: Addressed review comments from Ville:
- s/ycbcr_420_vdb/y420vdb
- s/ycbcr_420_vcb/y420cmdb
- Be less verbose on description of do_y420vdb_modes
- Move newmode variable in the loop scope.
- Use svd_to_vic() to get a VIC, instead of 0x7f
- Remove bitmap description for CMDB modes & VDB modes
- Dont add connector->ycbcr_420_allowed check for cmdb modes
- Remove 'len' variable, in is_y420cmdb function, which is used
only once
- Add length check in is_y420vdb function
- Remove unnecessary if (!db) check in function parse_y420cmdb_bitmap
- Do not add print about YCBCR 420 modes
- Fix indentation in few places
- Move ycbcr420_dc_modes in next patch, where its used
- Add a separate patch for movement of drm_add_display_info()
V5: Addressed review comments from Ville:
- Add the patch which cleans up the current EXTENDED_TAG usage
- Make y420_cmdb_map u64
- Do not block ycbcr420 modes while parsing the EDID, rather
add a separate helper function to prune ycbcr420-only modes from
connector's probed modes.
V6: Rebase
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 148 +++++++++++++++++++++++++++++++++++++++++++-
include/drm/drm_connector.h | 20 ++++++
2 files changed, 166 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 9a07f42..10dab62 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2783,6 +2783,8 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
#define SPEAKER_BLOCK 0x04
#define USE_EXTENDED_TAG 0x07
#define EXT_VIDEO_CAPABILITY_BLOCK 0x00
+#define EXT_VIDEO_DATA_BLOCK_420 0x0E
+#define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F
#define EDID_BASIC_AUDIO (1 << 6)
#define EDID_CEA_YCRCB444 (1 << 5)
#define EDID_CEA_YCRCB422 (1 << 4)
@@ -3154,15 +3156,79 @@ drm_display_mode_from_vic_index(struct drm_connector *connector,
return newmode;
}
+/*
+ * do_y420vdb_modes - Parse YCBCR 420 only modes
+ * @connector: connector corresponding to the HDMI sink
+ * @svds: start of the data block of CEA YCBCR 420 VDB
+ * @len: length of the CEA YCBCR 420 VDB
+ *
+ * Parse the CEA-861-F YCBCR 420 Video Data Block (Y420VDB)
+ * which contains modes which can be supported in YCBCR 420
+ * output format only.
+ */
+static int do_y420vdb_modes(struct drm_connector *connector,
+ const u8 *svds, u8 svds_len)
+{
+ int modes = 0, i;
+ struct drm_device *dev = connector->dev;
+ struct drm_display_info *info = &connector->display_info;
+ struct drm_hdmi_info *hdmi = &info->hdmi;
+
+ for (i = 0; i < svds_len; i++) {
+ u8 vic = svd_to_vic(svds[i]);
+ struct drm_display_mode *newmode;
+
+ newmode = drm_mode_duplicate(dev, &edid_cea_modes[vic]);
+ if (!newmode)
+ break;
+ bitmap_set(hdmi->y420_vdb_modes, vic, 1);
+ drm_mode_probed_add(connector, newmode);
+ modes++;
+ }
+
+ if (modes > 0)
+ info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
+ return modes;
+}
+
+/*
+ * drm_add_cmdb_modes - Add a YCBCR 420 mode into bitmap
+ * @connector: connector corresponding to the HDMI sink
+ * @vic: CEA vic for the video mode to be added in the map
+ *
+ * Makes an entry for a videomode in the YCBCR 420 bitmap
+ */
+static void
+drm_add_cmdb_modes(struct drm_connector *connector, u8 svd)
+{
+ u8 vic = svd_to_vic(svd);
+ struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+
+ bitmap_set(hdmi->y420_cmdb_modes, vic, 1);
+}
+
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;
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 CEA modes from CEA VDB, which
+ * can support YCBCR 420 sampling output also (apart
+ * from RGB/YCBCR444 etc).
+ * For example, if the bit 0 in bitmap is set,
+ * first mode in VDB can support YCBCR420 output too.
+ * Add YCBCR420 modes only if sink is HDMI 2.0 capable.
+ */
+ if (hdmi->y420_cmdb_map & (1 << i))
+ drm_add_cmdb_modes(connector, db[i]);
+
drm_mode_probed_add(connector, mode);
modes++;
}
@@ -3504,9 +3570,78 @@ 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)
+{
+
+ if (cea_db_tag(db) != USE_EXTENDED_TAG)
+ return false;
+
+ if (!cea_db_payload_len(db))
+ return false;
+
+ if (cea_db_extended_tag(db) != EXT_VIDEO_CAP_BLOCK_Y420CMDB)
+ return false;
+
+ return true;
+}
+
+static bool cea_db_is_y420vdb(const u8 *db)
+{
+ if (cea_db_tag(db) != USE_EXTENDED_TAG)
+ return false;
+
+ if (!cea_db_payload_len(db))
+ return false;
+
+ if (cea_db_extended_tag(db) != EXT_VIDEO_DATA_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_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 (map_len == 0) {
+ /* All CEA modes support ycbcr420 sampling also.*/
+ hdmi->y420_cmdb_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)
+ info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
+
+ hdmi->y420_cmdb_map = map;
+}
+
static int
add_cea_modes(struct drm_connector *connector, struct edid *edid)
{
@@ -3529,10 +3664,16 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
video = db + 1;
video_len = dbl;
modes += do_cea_modes(connector, video, dbl);
- }
- else if (cea_db_is_hdmi_vsdb(db)) {
+ } else if (cea_db_is_hdmi_vsdb(db)) {
hdmi = db;
hdmi_len = dbl;
+ } else if (cea_db_is_y420vdb(db)) {
+ const u8 *vdb420 = &db[2];
+
+ /* Add 4:2:0(only) modes present in EDID */
+ modes += do_y420vdb_modes(connector,
+ vdb420,
+ dbl - 1);
}
}
}
@@ -4215,6 +4356,8 @@ 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);
}
}
@@ -4476,6 +4619,7 @@ 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);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index ae5b7dc..b3af8e3 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -135,6 +135,25 @@ struct drm_scdc {
struct drm_hdmi_info {
/** @scdc: sink's scdc support and capabilities */
struct drm_scdc scdc;
+
+ /**
+ * @y420_vdb_modes: bitmap of modes which can support ycbcr420
+ * output only (not normal RGB/YCBCR444/422 outputs). There are total
+ * 107 VICs defined by CEA-861-F spec, so the size is 128 bits to map
+ * upto 128 VICs;
+ */
+ unsigned long y420_vdb_modes[BITS_TO_LONGS(128)];
+
+ /**
+ * @y420_cmdb_modes: bitmap of modes which can support ycbcr420
+ * output also, along with normal HDMI outputs. There are total 107
+ * VICs defined by CEA-861-F spec, so the size is 128 bits to map upto
+ * 128 VICs;
+ */
+ unsigned long y420_cmdb_modes[BITS_TO_LONGS(128)];
+
+ /** @y420_cmdb_map: bitmap of SVD index, to extraxt vcb modes */
+ u64 y420_cmdb_map;
};
/**
@@ -198,6 +217,7 @@ 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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