On Thu, Jun 15, 2017 at 09:05:10PM +0530, Sharma, Shashank wrote:
> 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.syrj...@linux.intel.com>
> >> Cc: Jose Abreu <joab...@synopsys.com>
> >> Cc: Emil Velikov <emil.l.veli...@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.sha...@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.
No, we should put into the probe helpers standard mode validation stuff.
No driver specifics needed apart from setting the support_ycbcr420 or
whatever flag.
> 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
And what happens when when you have an otherwise HDMI 2.0 capable
source that can't output YCbCr 4:2:0?
> 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()
Not in this patch.
> 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
--
Ville Syrjälä
Intel OTC
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