[PATCH v3 04/14] drm/edid: parse YCBCR 420 videomodes from EDID
Sharma, Shashank
shashank.sharma at intel.com
Thu Jun 15 15:35:10 UTC 2017
Regards
Shashank
On 6/15/2017 8:13 PM, Ville Syrjälä wrote:
> On Wed, Jun 14, 2017 at 11:17:35PM +0530, Shashank Sharma wrote:
>> 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.
>>
>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>> Cc: Jose Abreu <joabreu at synopsys.com>
>> Cc: Emil Velikov <emil.l.velikov at gmail.com>
>>
>> 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.
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>> ---
>> drivers/gpu/drm/drm_edid.c | 193 ++++++++++++++++++++++++++++++++++++++++++--
>> include/drm/drm_connector.h | 23 ++++++
>> 2 files changed, 211 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 6fd8a98..4953f87 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 +3145,103 @@ drm_display_mode_from_vic_index(struct drm_connector *connector,
>> return newmode;
>> }
>>
>> +/*
>> + * do_ycbcr_420_vdb_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
>> + *
>> + * CEA-861-F has added a new video block called YCBCR 420 Video
>> + * Data Block (ycbcr 420 vdb). This block contains modes which
>> + * support YCBCR 420 HDMI output (only YCBCR 420). This function
>> + * parses the block and adds these modes into connector's mode list.
> Seems a bit verbose. Maybe something like:
> "Parse the CEA-861-F YCbCr 4:2:0 Video Data Block (Y420VDB)
> which contains modes which only support YCbCr 4:2:0 output."
Got it.
>> + */
>> +static int do_ycbcr_420_vdb_modes(struct drm_connector *connector,
>> + const u8 *svds, u8 svds_len)
> Probably we could s/ycbcr_420_vdb/y420vdb/ all over to keep things
> shorter and match the terminology in the spec. Same for y420cmdb.
Got it.
>> +{
>> + int modes = 0, i;
>> + struct drm_device *dev = connector->dev;
>> + struct drm_display_mode *newmode;
> This variable can be moved into the loop scope.
Ok.
>> + struct drm_display_info *info = &connector->display_info;
>> + struct drm_hdmi_info *hdmi = &info->hdmi;
>> +
>> + for (i = 0; i < svds_len; i++) {
>> + u8 vic = svds[i] & 0x7f;
> What's the 0x7f here? Native bit stuff? I'm thinkign we probably want
> some kind of svd_to_vic() function to make sure everyone deals with
> this stuff correctly.
Current VICs are 1 < VIC < 108, so seven bits required to show a VIC.
This is inspired from
drm_mode_from_cea_vic_index().
>> +
>> + newmode = drm_mode_duplicate(dev, &edid_cea_modes[vic]);
>> + if (!newmode)
>> + break;
>> + /*
>> + * ycbcr420_vdb_modes is a fix position 128 bit bitmap.
>> + * Every bit here represents a VIC, from CEA-861-F list.
>> + * So if bit[n] is set, it indicates vic[n+1] supports
>> + * YCBCR420 output. Bit 0 is dummy, as VICs start at 1.
>> + * ycbcr420_vcb_modes[0] = |VIC=64 |VIC=63 |.....|VIC=2 |VIC=1 |
>> + * ycbcr420_vcb_modes[1] = |VIC=128|VIC=127|.....|VIC=66|VIC=65|
>> + */
> I think people can figure out how the standard bitmaps work without
> having to explain it with such detail. If you want to elaborate on the
> contents of the bitmap, then I think the comment should be next to
> where the bitmap is defined.
There is already similar explanation :), I will probably remove this.
>> + bitmap_set(hdmi->ycbcr420_vdb_modes, vic, 1);
> __set_bit()
Any harm on bitmap_set ? I guess this is specially for bitmaps ...
>
>> + drm_mode_probed_add(connector, newmode);
>> + modes++;
>> + }
>> +
>> + if (modes > 0)
>> + info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
>> + return modes;
>> +}
>> +
>> +/*
>> + * drm_add_vcb_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_vcb_modes(struct drm_connector *connector, u8 vic)
> The "vcb" term doesn't seem to be in the spec. Should be "cmdb" maybe?
>
> Or maybe we want ycbcr420_vdb_modes and ycbcr420_y420vdb_modes just to
> make it clear to which VDB they relate with.
cmdb seems appropriate, which is aligned to the spec too, will do the
change.
>
>> +{
>> + 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.
>> + * Every bit here represents a VIC, from CEA-861-F list.
>> + * So if bit[n] is set, it indicates vic[n+1] supports
>> + * YCBCR420 output. Bit 0 is dummy, as VICs start at 1.
>> + * ycbcr420_vcb_modes[0] = |VIC=64 |VIC=63 |.....|VIC=2 |VIC=1 |
>> + * ycbcr420_vcb_modes[1] = |VIC=128|VIC=127|.....|VIC=66|VIC=65|
>> + * Difference between a vcb_mode and vdb_mode is that a vcb_mode
>> + * can support other HDMI outputs like RGB/YCBCR444/422 also
>> + * along with YCBCR 240, whereas a vdb_mode can only support YCBCR
>> + * 420 HDMI output.
>> + */
>> + bitmap_set(hdmi->ycbcr420_vcb_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 (connector->is_hdmi2_src &&
> Hmm. I wonder if need this here at all. I guess we do need something for
> the "420 only" modes, but not sure if it should be here or if we should
> reject them only during mode validation. The latter would be nice
> because it would then leave a message into the log that the mode was
> present but was rejected.
Seems like a good idea, the only benefit of doing this is, this is in
DRM layer, and will protect other drivers
from accidentally adding 420_vcb modes. Mode valid would be internal to
driver, and applicable in I915 layer.
So your wish is my command :)
> I'm thinking we should probably call this
> flag ycbcr420_allowed or something like that to match the other
> foo_allowed flags we have in the connector for mode validation.
I don't like that honestly. I am hoping that this flag would be used
further, to identify a HDMI 2.0 src over HDMI 1.4
source, beyond YCBCR420 feature, and at that time, it might be more
suitable to have hdmi_2_src. Does it make sense ?
> So I think this could perhaps just be an uncoditional
> if (test_bit(i, ...))
> __set_bit(vic, ...);
>
>> + test_bit(i, &hdmi->ycbcr420_vcb_map))
>> + drm_add_vcb_modes(connector, db[i]);
>> +
>> drm_mode_probed_add(connector, mode);
>> modes++;
>> }
>> @@ -3427,6 +3517,12 @@ 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];
>> +}
> Could you clean up the current extended tag usage as a separate
> prep patch? Would be nice to avoid the confusion of calling the
> "Use extended tag" tag VIDEO_CAPABILITY_BLOCK.
Sure, adding in my to-do list.
>> +
>> +static int
>> cea_db_payload_len(const u8 *db)
>> {
>> return db[0] & 0x1f;
>> @@ -3487,9 +3583,81 @@ static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)
>> return oui == HDMI_FORUM_IEEE_OUI;
>> }
>>
>> +static bool cea_db_is_ycbcr_420_cmdb(const u8 *db)
>> +{
>> + u8 len = cea_db_payload_len(db);
> 'len' seems like a fairly pointless variable since it's used exactly
> once.
Agree,
>
>> +
>> + 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;
>> +}
>> +
>> +static bool cea_db_is_ycbcr_420_vdb(const u8 *db)
>> +{
>> + if (cea_db_tag(db) != VIDEO_CAPABILITY_BLOCK)
>> + return false;
>> +
> Length check missing.
Oops, got it.
>> + if (cea_db_extended_tag(db) != 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 (!db)
>> + return;
> Can't happen.
I assumed you were convince on my previous (lame) excuse of corrupt db :)
Will remove this check.
>
>> +
>> + 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");
> If we want to print something about the sinks color capabilities I think
> it should be in central place instead of being sprinkled all over the
> place.
Yes, seems like a good idea. I will remove this, and may be add a
separate patch to dump
sink capabilities.
>> + info->color_formats |= DRM_COLOR_FORMAT_YCRCB420;
>> + }
>> +
>> + hdmi->ycbcr420_vcb_map = map;
>> +}
>> +
>> static int
>> add_cea_modes(struct drm_connector *connector, struct edid *edid)
>> {
>> @@ -3512,10 +3680,17 @@ 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_ycbcr_420_vdb(db) &&
>> + connector->is_hdmi2_src) {
> Broken indentation in a bunch of places.
Damn, I thought I am improving :(
>
>> + const u8 *vdb420 = &db[2];
>> +
>> + /* Add 4:2:0(only) modes present in EDID */
>> + modes += do_ycbcr_420_vdb_modes(connector,
>> + vdb420,
>> + dbl - 1);
>> }
>> }
>> }
>> @@ -4196,6 +4371,8 @@ 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_ycbcr_420_cmdb(db))
>> + drm_parse_y420cmdb_bitmap(connector, db);
>> }
>> }
>>
>> @@ -4430,6 +4607,13 @@ 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 +4634,13 @@ 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);
>> -
> I think this could be a separate patch, just in case it causes a
> regression.
Got it.
>
>> 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 390319c..5a47c33 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -137,6 +137,28 @@ struct drm_scdc {
>> struct drm_hdmi_info {
>> /** @scdc: sink's scdc support and capabilities */
>> struct drm_scdc scdc;
>> +
>> + /**
>> + * @ycbcr420_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 ycbcr420_vdb_modes[BITS_TO_LONGS(128)];
>> +
>> + /**
>> + * @ycbcr420_vcb_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 ycbcr420_vcb_modes[BITS_TO_LONGS(128)];
>> +
>> + /** @ycbcr420_vcb_map: bitmap of SVD index, to extraxt vcb modes */
>> + unsigned long ycbcr420_vcb_map;
>> +
>> + /** @ycbcr420_dc_modes: bitmap of deep color support index */
>> + u8 ycbcr420_dc_modes;
> unused
Its used. We are parsing 420 deep color info and checking the it in
hdmi_12bpc_possible()
Shashank
>
>> };
>>
>> /**
>> @@ -200,6 +222,7 @@ 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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