On Wed, Aug 14, 2013 at 12:08:13PM -0400, Alex Deucher wrote:
> 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
>
> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++
> include/drm/drm_edid.h | 1 +
> 2 files changed, 53 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 70fc133..2e36d28 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 = kcalloc(count, dbl, GFP_KERNEL);
'count' not initialized yet. I suppose it was supposed to be just
kmalloc(dbl, GFP_KERNEL). But since it's just three bytes, making
the user just pass in a pointer to u32 would work just as well
w/o requiring the dynamic alloc/free.
> + 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
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index fc481fc..c76a129 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -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,
> --
> 1.8.3.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel OTC
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