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Commit d105f476 authored by Alex Deucher's avatar Alex Deucher
Browse files

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: default avatarAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: default avatarRafał Miłecki <zajec5@gmail.com>
parent 2483b4ea

drivers/gpu/drm/drm_edid.c

+52 −0
Original line number Diff line number Diff line
@@ -2734,6 +2734,58 @@ 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

include/drm/drm_edid.h

+1 −0
Original line number Diff line number Diff line
@@ -259,6 +259,7 @@ 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_edid_to_speaker_allocation(struct edid *edid, u8 **sadb);

int drm_av_sync_delay(struct drm_connector *connector,

		      struct drm_display_mode *mode);

struct drm_connector *drm_select_eld(struct drm_encoder *encoder,