diff options
Diffstat (limited to 'sound/usb/card.c')
| -rw-r--r-- | sound/usb/card.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c index a0087bde684c..6c5b0e02e57b 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -120,6 +120,38 @@ static struct snd_usb_audio *usb_chip[SNDRV_CARDS]; static struct usb_driver usb_audio_driver; /* + * Checks to see if requested audio profile, i.e sample rate, # of + * channels, etc... is supported by the substream associated to the + * USB audio device. + */ +struct snd_usb_stream * +snd_usb_find_suppported_substream(int card_idx, struct snd_pcm_hw_params *params, + int direction) +{ + struct snd_usb_audio *chip; + struct snd_usb_substream *subs; + struct snd_usb_stream *as; + + /* + * Register mutex is held when populating and clearing usb_chip + * array. + */ + guard(mutex)(®ister_mutex); + chip = usb_chip[card_idx]; + + if (chip && enable[card_idx]) { + list_for_each_entry(as, &chip->pcm_list, list) { + subs = &as->substream[direction]; + if (snd_usb_find_substream_format(subs, params)) + return as; + } + } + + return NULL; +} +EXPORT_SYMBOL_GPL(snd_usb_find_suppported_substream); + +/* * disconnect streams * called from usb_audio_disconnect() */ |