missing sound on kernel-5.15

[Takashi Iwai]

On Thu, 01 Sep 2022 12:06:25 +0200,
chihhao chen wrote:
> 
> Hi Takashi,
> 
> I tested the patch and USB audio function works well.
> (Start and stop playback more than 20 times with Samsung USB C
> Earphone)

Great, thanks for quick testing!


Takashi

> 
> Thanks
> 
> On Thu, 2022-09-01 at 10:28 +0200, Takashi Iwai wrote:
> > On Thu, 01 Sep 2022 09:51:37 +0200,
> > Takashi Iwai wrote:
> > > 
> > > On Thu, 01 Sep 2022 07:50:40 +0200,
> > > chihhao chen wrote:
> > > > 
> > > > Hi Takashi,
> > > > 
> > > > The patch fixes this problem.
> > > > I tried it with "Product: Samsung USB C Earphone" and missing
> > > > sound
> > > > problem cannot be reproduced.
> > > 
> > > OK, it's a good news.  I'm going to add more information to the
> > > patch
> > > description about the regression and submit the patch.
> > 
> > Could you check whether the below cleanup patch on top of the
> > previous
> > one doesn't break things?  I lightly tested on my devices and don't
> > believe it would change the actual behavior, but just to be sure.
> > 
> > 
> > Takashi
> > 
> > -- 8< --
> > From: Takashi Iwai <tiwai at suse.de>
> > Subject: [PATCH] ALSA: usb-audio: Clean up endpoint setups at PCM
> > prepare
> > 
> > This patch cleans up the superfluous checks and calls for setting up
> > the endpoints at PCM prepare callback:
> > 
> > - Drop stop_endpoints() and sync_pending_stops() calls; the stream is
> >   guaranteed to have been already stopped and synced at each PCM
> >   prepare call by ALSA PCM core
> > 
> > - Call snd_usb_endpoint_prepare() unconditionally;
> >   the check for endpoint->need_setup is done in
> >   snd_pcm_hw_endpoint_prepare() itself
> > 
> > - Apply snd_usb_set_format_quirk() only when the endpoint is actually
> >   set up (i.e. the return code from snd_usb_endpoint_prepare() > 0)
> > 
> > - Move a few lines back into snd_usb_pcm_prepare();
> >   it's even easier to follow than a small useless function
> > 
> > Signed-off-by: Takashi Iwai <tiwai at suse.de>
> > ---
> >  sound/usb/pcm.c | 40 ++++++++++------------------------------
> >  1 file changed, 10 insertions(+), 30 deletions(-)
> > 
> > diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> > index b604f7e95e82..4ed53a3dc922 100644
> > --- a/sound/usb/pcm.c
> > +++ b/sound/usb/pcm.c
> > @@ -433,35 +433,6 @@ static void close_endpoints(struct snd_usb_audio
> > *chip,
> >  	}
> >  }
> >  
> > -static int configure_endpoints(struct snd_usb_audio *chip,
> > -			       struct snd_usb_substream *subs)
> > -{
> > -	int err;
> > -
> > -	if (subs->data_endpoint->need_setup) {
> > -		/* stop any running stream beforehand */
> > -		if (stop_endpoints(subs, false))
> > -			sync_pending_stops(subs);
> > -		if (subs->sync_endpoint) {
> > -			err = snd_usb_endpoint_prepare(chip, subs-
> > >sync_endpoint);
> > -			if (err < 0)
> > -				return err;
> > -		}
> > -		err = snd_usb_endpoint_prepare(chip, subs-
> > >data_endpoint);
> > -		if (err < 0)
> > -			return err;
> > -		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
> > -	} else {
> > -		if (subs->sync_endpoint) {
> > -			err = snd_usb_endpoint_prepare(chip, subs-
> > >sync_endpoint);
> > -			if (err < 0)
> > -				return err;
> > -		}
> > -	}
> > -
> > -	return 0;
> > -}
> > -
> >  /*
> >   * hw_params callback
> >   *
> > @@ -640,9 +611,18 @@ static int snd_usb_pcm_prepare(struct
> > snd_pcm_substream *substream)
> >  		goto unlock;
> >  	}
> >  
> > -	ret = configure_endpoints(chip, subs);
> > +	if (subs->sync_endpoint) {
> > +		ret = snd_usb_endpoint_prepare(chip, subs-
> > >sync_endpoint);
> > +		if (ret < 0)
> > +			goto unlock;
> > +	}
> > +
> > +	ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
> >  	if (ret < 0)
> >  		goto unlock;
> > +	else if (ret > 0)
> > +		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
> > +	ret = 0;
> >  
> >  	/* reset the pointer */
> >  	subs->buffer_bytes = frames_to_bytes(runtime, runtime-
> > >buffer_size);
>