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author | Rafał Miłecki <zajec5@gmail.com> | 2013-04-19 19:01:25 +0200 |
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committer | Alex Deucher <alexander.deucher@amd.com> | 2013-04-23 18:03:58 -0400 |
commit | fe214163cc6e6b33253b7ac14bc3dd616e76b513 (patch) | |
tree | 32c17795c76da99c458c61f71127d4897f82deb3 /drivers/gpu/drm/drm_edid.c | |
parent | 205996c0776a229052c33688ee58a605a021740d (diff) | |
download | linux-fe214163cc6e6b33253b7ac14bc3dd616e76b513.tar.bz2 |
drm: add drm_edid_to_eld helper extracting SADs from EDID (v2)
Some devices (ATI/AMD cards) don't support passing ELD struct to the
hardware but just require filling specific registers and then the
hardware/firmware does the rest. In such cases we need to read the info
from SAD blocks and put them in the correct registers.
agd5f: note that the returned pointer needs to be kfreed as per
Christian's suggestion.
v2: fix warning
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
-rw-r--r-- | drivers/gpu/drm/drm_edid.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index e2acfdbf7d3c..b6807e881a60 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -2511,6 +2511,65 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) EXPORT_SYMBOL(drm_edid_to_eld); /** + * drm_edid_to_sad - extracts SADs from EDID + * @edid: EDID to parse + * @sads: pointer that will be set to the extracted SADs + * + * Looks for CEA EDID block and extracts SADs (Short Audio Descriptors) from it. + * Note: returned pointer needs to be kfreed + * + * Return number of found SADs or negative number on error. + */ +int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads) +{ + int count = 0; + int i, start, end, dbl; + 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) { + u8 *db = &cea[i]; + + if (cea_db_tag(db) == AUDIO_BLOCK) { + int j; + dbl = cea_db_payload_len(db); + + count = dbl / 3; /* SAD is 3B */ + *sads = kcalloc(count, sizeof(**sads), GFP_KERNEL); + if (!*sads) + return -ENOMEM; + for (j = 0; j < count; j++) { + u8 *sad = &db[1 + j * 3]; + + (*sads)[j].format = (sad[0] & 0x78) >> 3; + (*sads)[j].channels = sad[0] & 0x7; + (*sads)[j].freq = sad[1] & 0x7F; + (*sads)[j].byte2 = sad[2]; + } + break; + } + } + + return count; +} +EXPORT_SYMBOL(drm_edid_to_sad); + +/** * 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 |