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drm: add drm_edid_to_eld helper extracting SADs from EDID (v2)

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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>
This commit is contained in:
Rafał Miłecki 2013-04-19 19:01:25 +02:00 committed by Alex Deucher
parent 205996c077
commit fe214163cc
2 changed files with 68 additions and 0 deletions
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59
drivers/gpu/drm/drm_edid.c
View file

@ -2510,6 +2510,65 @@ 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

9
include/drm/drm_edid.h
View file

@ -244,12 +244,21 @@ struct edid {
#define EDID_PRODUCT_ID(e) ((e)->prod_code[0] | ((e)->prod_code[1] << 8))
/* Short Audio Descriptor */
struct cea_sad {
u8 format;
u8 channels; /* max number of channels - 1 */
u8 freq;
u8 byte2; /* meaning depends on format */
};
struct drm_encoder;
struct drm_connector;
struct drm_display_mode;
struct hdmi_avi_infoframe;
void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid);
int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads);
int drm_av_sync_delay(struct drm_connector *connector,
struct drm_display_mode *mode);
struct drm_connector *drm_select_eld(struct drm_encoder *encoder,