On Fri, Mar 11, 2016 at 03:36:48PM +0200, Jani Nikula wrote: > 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... ;) Since sad_count will not exceed 15-total_sad_count, total_sad_count will never exceed 15. > > 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 -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
