Commit fe214163 authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Alex Deucher
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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: default avatarRafał Miłecki <zajec5@gmail.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 205996c0

drivers/gpu/drm/drm_edid.c

+59 −0
Original line number Diff line number Diff line
@@ -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

include/drm/drm_edid.h

+9 −0
Original line number Diff line number Diff line
@@ -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,

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