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| author | Jani Nikula <jani.nikula@intel.com> | 2022-06-08 10:50:31 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2022-06-13 12:30:16 +0300 |
| commit | fc67615f4ecc3b66bd458840927272aa131eface (patch) | |
| tree | 2309a35f84d8b7d563a4786002c919bedba4a3c8 /drivers/gpu | |
| parent | f4e3a12bf2d1983b8f352b7719794c52be7e0990 (diff) | |
| download | linux-fc67615f4ecc3b66bd458840927272aa131eface.tar.xz | |
drm/edid: fix CTA data block collection size for CTA version 3
The CTA Data Block Collection is valid only for CTA extension version
3. In versions 1 and 2, it is a reserved block, which we ignore.
The DTD start offset (byte 2, or d in CTA-861 spec), which determines
the CTA Data Block Collection size, is specified slightly differently
for different versions:
Version 1:
d = offset for the byte following the reserved data block. If no
data is provided in the reserved data block, then d=4. If no DTDs
are provided, then d=0
Version 2:
d = offset for the byte following the reserved data block. If no
data is provided in the reserved data block, then d=4. If d=0, then
no detailed timing descriptors are provided, and no data is provided
in the reserved data block.
Version 3:
d = offset for the byte following the data block collection. If no
data is provided in the data block collection, then d=4. If d=0,
then no detailed timing descriptors are provided, and no data is
provided in the data block collection.
Ever since commit 9e50b9d55e9c ("drm: edid: Add some bounds checking"),
we've interpreted 0 to mean there are no DTDs but it's all Data
Blocks. Per the spec, Data Blocks are only valid for version 3, where we
should interpret 0 to mean there are no data blocks.
Follow the spec (and hope the EDIDs follow it too).
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/2a4c94417f024cbafc5d4ca0a74e4617fc4325d1.1654674560.git.jani.nikula@intel.com
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 929fc0e46751..c57f6333ea7d 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -4498,8 +4498,6 @@ static const void *__cea_db_iter_edid_next(struct cea_db_iter *iter) iter->index = 4; iter->end = ext[2]; - if (iter->end == 0) - iter->end = 127; if (iter->end < 4 || iter->end > 127) continue; |