On Fri, Mar 11, 2016 at 04:24:35PM +0200, Jani Nikula wrote: > On Fri, 11 Mar 2016, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > [ text/plain ] > > 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. > > Right. I guess it could be spelled out for folks like me. :/ > > Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> > > 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. Applied to drm-misc but not yet pushed since I want to roll forward to latest drm-next as soon as Dave has merged everything. -Daniel > > 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 > > -- > Jani Nikula, Intel Open Source Technology Center > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
