| Date | Tue, 25 Jul 2023 08:57:34 +0200 | From | Takashi Iwai <> | Subject | Re: [PATCH v4 19/32] sound: usb: card: Check for support for requested audio format |
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On Tue, 25 Jul 2023 04:34:03 +0200, Wesley Cheng wrote: > > 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 > initiated by the ASoC USB backend path. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/card.c | 28 ++++++++++++++++++++++++++++ > sound/usb/card.h | 8 ++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/sound/usb/card.c b/sound/usb/card.c > index a3fad66a3337..365f6d978608 100644 > --- a/sound/usb/card.c > +++ b/sound/usb/card.c > @@ -142,6 +142,34 @@ int snd_usb_unregister_platform_ops(void) > } > EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops); > > +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, > + struct snd_pcm_hw_params *params, int direction) > +{
Please add a comment what this function does.
> + struct snd_usb_audio *chip = usb_chip[card_idx];
Is the dereference safe without locking? If the call is supposed to be allowed only in a safe situation, it should be mentioned in the function description.
thanks,
Takashi
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