diff options
| author | Alex Deucher <alexander.deucher@amd.com> | 2013-07-25 15:55:32 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2013-08-30 16:30:43 -0400 |
| commit | d105f4768a959f22078820625ccec9b693f164c8 (patch) | |
| tree | c09baba606b7ef14401adb0e6b9eaa6ab1b723a0 /drivers/gpu/drm/drm_edid.c | |
| parent | 2483b4ea982efe8a544697d3f9642932e9af4dc1 (diff) | |
drm/edid: add a helper function to extract the speaker allocation data block (v3)
This adds a helper function to extract the speaker allocation
data block from the EDID. This data block describes what speakers
are present on the display device.
v2: update per Ville Syrjälä's comments
v3: fix copy/paste typo in memory allocation
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 70fc1335e33..58b4882feed 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -2735,6 +2735,58 @@ int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads) EXPORT_SYMBOL(drm_edid_to_sad); /** + * drm_edid_to_speaker_allocation - extracts Speaker Allocation Data Blocks from EDID + * @edid: EDID to parse + * @sadb: pointer to the speaker block + * + * Looks for CEA EDID block and extracts the Speaker Allocation Data Block from it. + * Note: returned pointer needs to be kfreed + * + * Return number of found Speaker Allocation Blocks or negative number on error. + */ +int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb) +{ + int count = 0; + int i, start, end, dbl; + const u8 *cea; + + cea = drm_find_cea_extension(edid); + if (!cea) { + DRM_DEBUG_KMS("SAD: no CEA Extension found\n"); + return -ENOENT; + } + + if (cea_revision(cea) < 3) { + DRM_DEBUG_KMS("SAD: wrong CEA revision\n"); + return -ENOTSUPP; + } + + if (cea_db_offsets(cea, &start, &end)) { + DRM_DEBUG_KMS("SAD: invalid data block offsets\n"); + return -EPROTO; + } + + for_each_cea_db(cea, i, start, end) { + const u8 *db = &cea[i]; + + if (cea_db_tag(db) == SPEAKER_BLOCK) { + dbl = cea_db_payload_len(db); + + /* Speaker Allocation Data Block */ + if (dbl == 3) { + *sadb = kmalloc(dbl, GFP_KERNEL); + memcpy(*sadb, &db[1], dbl); + count = dbl; + break; + } + } + } + + return count; +} +EXPORT_SYMBOL(drm_edid_to_speaker_allocation); + +/** * drm_av_sync_delay - HDMI/DP sink audio-video sync delay in millisecond * @connector: connector associated with the HDMI/DP sink * @mode: the display mode |