Re: [PATCH v9 27/34] ALSA: usb-audio: qcom: Populate PCM and USB chip information

[Wesley Cheng]

Hi Pierre,

On 10/17/2023 3:41 PM, Pierre-Louis Bossart wrote:
> On 10/17/23 15:01, Wesley Cheng wrote:
> > Currently, only the index to the USB SND card array is passed to the USB
> > backend.  Pass through more information, specifically the USB SND card
> > number and the number of PCM devices available.  This allows for the DPCM
> > backend to determine what USB resources are available during situations,
> > such as USB audio offloading.
> >
> > Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
> > ---
> >   sound/usb/qcom/qc_audio_offload.c | 21 ++++++++++++++++++---
> >   1 file changed, 18 insertions(+), 3 deletions(-)
> >
> > diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
> > index bd6b84f72c74..ae74098b41f5 100644
> > --- a/sound/usb/qcom/qc_audio_offload.c
> > +++ b/sound/usb/qcom/qc_audio_offload.c
> > @@ -173,6 +173,21 @@ enum usb_qmi_audio_format {
> >   	USB_QMI_PCM_FORMAT_U32_BE,
> >   };
> >   
> > +static int usb_qmi_get_pcm_num(struct snd_usb_audio *chip, int direction)
> > +{
> > +	struct snd_usb_substream *subs = NULL;
> > +	struct snd_usb_stream *as;
> > +	int count = 0;
> > +
> > +	list_for_each_entry(as, &chip->pcm_list, list) {
> > +		subs = &as->substream[direction];
> > +		if (subs->ep_num)
> > +			count++;
> > +	}
> > +
> > +	return count;
> > +}
> > +
> >   static enum usb_qmi_audio_device_speed_enum_v01
> >   get_speed_info(enum usb_device_speed udev_speed)
> >   {
> > @@ -1592,6 +1607,8 @@ static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip)
> >   
> >   	sdev->card_idx = chip->card->number;
> >   	sdev->chip_idx = chip->index;
> > +	sdev->num_playback = usb_qmi_get_pcm_num(chip, 0);
> > +	sdev->num_capture = usb_qmi_get_pcm_num(chip, 1);
> >   	uadev[chip->card->number].sdev = sdev;
> >   
> >   	uaudio_qdev->last_card_num = chip->card->number;
> > @@ -1706,10 +1723,8 @@ static void qc_usb_audio_offload_disconnect(struct snd_usb_audio *chip)
> >   	mutex_unlock(&chip->mutex);
> >   
> >   	atomic_dec(&uaudio_qdev->qdev_in_use);
> > -	if (!atomic_read(&uaudio_qdev->qdev_in_use)) {
> > -		snd_soc_usb_disconnect(usb_get_usb_backend(udev));
>
> this also feels like a patch split issue, removing this
> snd_soc_usb_disconnect() has nothing to do with the "populate PCM and
> USB chip information" ?

Will fix this.

Thanks
Wesley Cheng