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@xxxxxxx>
---
sound/usb/implicit.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/sound/usb/implicit.c b/sound/usb/implicit.c
index 931042a6a051..9724efe1cdce 100644
--- a/sound/usb/implicit.c
+++ b/sound/usb/implicit.c
@@ -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,
--
2.26.2
