On Wed, 09 Mar 2016, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > 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@xxxxxxxxx> > Tested-by: Arturo Pérez <artur999555@xxxxxxxxx> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197 > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > 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... ;) 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 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel