Re: [PATCH v1 2/3] sound: usb: Calling vendor's call-back function within usb audio operation.

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Mar 24, 2022 at 05:10:43PM +0900, Oh Eomji wrote:
> When a new interface is connected or removed, the call-back functions
> are called to transmit a command to the hardware.
> 
> Signed-off-by: Oh Eomji <eomji.oh@samsung.com>
> ---
>  sound/usb/pcm.c    | 37 +++++++++++++++++++++++++++++++++++++
>  sound/usb/stream.c |  2 ++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index cec6e91a..4bae4ba 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -144,6 +144,8 @@ find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
>  			found = fp;
>  			cur_attr = attr;
>  		}
> +
> +		snd_vendor_set_pcm_binterval(fp, found, &cur_attr, &attr);
>  	}
>  	return found;
>  }
> @@ -434,6 +436,7 @@ static int configure_endpoints(struct snd_usb_audio *chip,
>  			       struct snd_usb_substream *subs)
>  {
>  	int err;
> +	struct usb_interface *iface;
>  
>  	if (subs->data_endpoint->need_setup) {
>  		/* stop any running stream beforehand */
> @@ -442,6 +445,13 @@ static int configure_endpoints(struct snd_usb_audio *chip,
>  		err = snd_usb_endpoint_configure(chip, subs->data_endpoint);
>  		if (err < 0)
>  			return err;
> +
> +		iface = usb_ifnum_to_if(chip->dev, subs->data_endpoint->iface);
> +		err = snd_vendor_set_pcm_intf(iface, subs->data_endpoint->iface,
> +				subs->data_endpoint->altsetting, subs->direction);
> +		if (err < 0)
> +			return err;
> +
>  		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
>  	}
>  
> @@ -616,8 +626,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
>  	struct snd_pcm_runtime *runtime = substream->runtime;
>  	struct snd_usb_substream *subs = runtime->private_data;
>  	struct snd_usb_audio *chip = subs->stream->chip;
> +	struct snd_usb_endpoint *ep = subs->data_endpoint;
>  	int ret;
>  
> +	ret = snd_vendor_set_pcm_buf(subs->dev, subs->cur_audiofmt->iface);
> +	if (ret)
> +		return ret;
> +
> +	if (!subs->cur_audiofmt) {
> +		dev_err(&subs->dev->dev, "no format is specified\n");
> +		return -ENXIO;
> +	}
> +
>  	ret = snd_usb_lock_shutdown(chip);
>  	if (ret < 0)
>  		return ret;
> @@ -630,6 +650,13 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
>  	if (ret < 0)
>  		goto unlock;
>  
> +	if (snd_vendor_get_ops()) {
> +		ret = snd_vendor_set_rate(ep->cur_audiofmt->iface,
> +				ep->cur_rate, ep->cur_audiofmt->altsetting);
> +		if (!ret)
> +			goto unlock;
> +	}
> +
>  	/* reset the pointer */
>  	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
>  	subs->inflight_bytes = 0;
> @@ -1104,6 +1131,11 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
>  	struct snd_usb_substream *subs = &as->substream[direction];
>  	int ret;
>  
> +	ret = snd_vendor_set_pcm_connection(subs->dev, SOUND_PCM_OPEN,
> +					    direction);
> +	if (ret)
> +		return ret;
> +
>  	runtime->hw = snd_usb_hardware;
>  	/* need an explicit sync to catch applptr update in low-latency mode */
>  	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
> @@ -1137,6 +1169,11 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
>  	struct snd_usb_substream *subs = &as->substream[direction];
>  	int ret;
>  
> +	ret = snd_vendor_set_pcm_connection(subs->dev, SOUND_PCM_CLOSE,
> +					    direction);
> +	if (ret)
> +		return ret;
> +
>  	snd_media_stop_pipeline(subs);
>  
>  	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index ceb93d7..26ca696 100644
> --- a/sound/usb/stream.c
> +++ b/sound/usb/stream.c
> @@ -1227,6 +1227,8 @@ static int __snd_usb_parse_audio_interface(struct snd_usb_audio *chip,
>  		snd_usb_init_pitch(chip, fp);
>  		snd_usb_init_sample_rate(chip, fp, fp->rate_max);
>  		usb_set_interface(chip->dev, iface_no, altno);
> +		if (protocol > UAC_VERSION_1)

Why the protocol check?  That's not documented in your changelog
anywhere :(