Hi Pierre,

On 10/17/2023 3:29 PM, Pierre-Louis Bossart wrote:

On 10/17/23 15:00, Wesley Cheng wrote:

quoted

Allow for checks on a specific USB audio device to see if a requested PCM
format is supported.  This is needed for support for when playback is

This is needed for support when playback is

Will fix this typo

quoted

initiated by the ASoC USB backend path.

Signed-off-by: Wesley Cheng <redacted>
---
  sound/usb/card.c | 40 ++++++++++++++++++++++++++++++++++++++++
  sound/usb/card.h | 11 +++++++++++
  2 files changed, 51 insertions(+)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index c0b312e264bf..88f431917c15 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c

@@ -162,6 +162,46 @@ int snd_usb_unregister_platform_ops(void)
  }
  EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);
  
+/*
+ * 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 = NULL;

useless init?

Agreed.

Thanks
Wesley Cheng