On Fri, 11 Mar 2016, Ville Syrjälä ville.syrjala@linux.intel.com wrote:
[ text/plain ] On Fri, Mar 11, 2016 at 03:36:48PM +0200, Jani Nikula wrote:
On Wed, 09 Mar 2016, ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
SADs may span multiple CEA audio data blocks in the EDID.
CEA-861-E says: "The order of the Data Blocks is not constrained. It is also possible to have more than one of a specific type of data block if necessary to include all of the descriptors needed to describe the sink’s capabilities."
Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit is 15 according to HDA 1.0a spec. So we should support at least two data blocks. And apparently some devices take a more liberal interpretation and stuff only one SAD per data block even when they would fit into one.
So let's try to extract all the SADs we can fit into the ELD even when they span multiple data blocks.
While at it, toss in a comment to explain the 13 byte monitor name string limit which confused me at first.
Cc: Arturo Pérez artur999555@gmail.com Tested-by: Arturo Pérez artur999555@gmail.com Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197 Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_edid.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index fdb1eb014586..414d7f61aa05 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) u8 *cea; u8 *name; u8 *db;
- int sad_count = 0;
- int total_sad_count = 0; int mnl; int dbl;
@@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
name = NULL; drm_for_each_detailed_block((u8 *)edid, monitor_name, &name);
- /* max: 13 bytes EDID, 16 bytes ELD */ for (mnl = 0; name && mnl < 13; mnl++) { if (name[mnl] == 0x0a) break;
@@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) dbl = cea_db_payload_len(db);
switch (cea_db_tag(db)) {
int sad_count;case AUDIO_BLOCK: /* Audio Data Block, contains SADs */
sad_count = dbl / 3;if (dbl >= 1)memcpy(eld + 20 + mnl, &db[1], dbl);
sad_count = min(dbl / 3, 15 - total_sad_count);What if total_sad_count > 15? At a glance, this seems to self correct by subtracting the excess every second time... ;)
Since sad_count will not exceed 15-total_sad_count, total_sad_count will never exceed 15.
Right. I guess it could be spelled out for folks like me. :/
Reviewed-by: Jani Nikula jani.nikula@intel.com
If you run out of things to do (that'll be the day), you could follow up with replacing some of the magic here for offsets etc. with the DRM_ELD_* defines I added in drm_edid.h.
BR, Jani.
BR, Jani.
if (sad_count >= 1)memcpy(eld + 20 + mnl + total_sad_count * 3,&db[1], sad_count * 3);total_sad_count += sad_count; break; case SPEAKER_BLOCK: /* Speaker Allocation Data Block */@@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) } } }
- eld[5] |= sad_count << 4;
eld[5] |= total_sad_count << 4;
eld[DRM_ELD_BASELINE_ELD_LEN] = DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);
DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
drm_eld_size(eld), sad_count);
drm_eld_size(eld), total_sad_count);} EXPORT_SYMBOL(drm_edid_to_eld);
-- Jani Nikula, Intel Open Source Technology Center