@@ -378,20 +378,19 @@ snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
int stream)
{
struct snd_usb_substream *subs;
- const struct audioformat *fp, *sync_fmt;
+ const struct audioformat *fp, *sync_fmt = NULL;
int score, high_score;
- /* When sharing the same altset, use the original audioformat */
+ /* Use the original audioformat as fallback for the shared altset */
if (target->iface == target->sync_iface &&
target->altsetting == target->sync_altsetting)
- return target;
+ sync_fmt = target;
subs = find_matching_substream(chip, stream, target->sync_ep,
target->fmt_type);
if (!subs)
- return NULL;
+ return sync_fmt;
- sync_fmt = NULL;
high_score = 0;
list_for_each_entry(fp, &subs->fmt_list, list) {
score = match_endpoint_audioformats(subs, fp,
The implicit feedback mode needs to handle two endpoints and the choice of the audioformat object for the sync EP is important since this determines the compatibility of the hw_params. The current code uses the same audioformat object if both the main EP and the sync EP point to the same iface/altsetting. This was done in consideration of the non-implicit-fb sync EP handling, and it doesn't match well with the cases where actually to endpoints are defined in the sameiface / altsetting like a few Pioneer devices. Modify snd_usb_find_implicit_fb_sync_format() to pick up the audioformat that is assigned in the counter-part substreams primarily, so that the actual capture stream can be opened properly. We keep the same audioformat object only as a fallback in case nothing found, though. Fixes: 9fddc15e8039 ("ALSA: usb-audio: Factor out the implicit feedback quirk code") Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/usb/implicit.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)