Re: kern/52781: audioctl can't set output gain

[Nathanial Sloss <nat%netbsd.org@localhost>]

The following reply was made to PR kern/52781; it has been noted by GNATS.

From: Nathanial Sloss <nat%netbsd.org@localhost>
To: matthew green <mrg%eterna.com.au@localhost>
Cc: gnats-bugs%netbsd.org@localhost,
 kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost,
 bouyer%antioche.eu.org@localhost,
 matthew green <mrg%eterna.com.au@localhost>
Subject: Re: kern/52781: audioctl can't set output gain
Date: Sun, 20 May 2018 20:27:59 +1000

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 Hi,
 
 I've come up with an alternative.  See attached.
 
 In this patch audioctl devices default to the mix ring allowig hw gain to be 
 adjusted (recording/ play back/ balance).  If one were to issue audioctl 
 without specifing -p vchan it would set the hw paramaters one could still issue 
 audioctl -p 0 to achieve the same thing.
 
 It would mean existing sun audio apps that set the master volume via 
 play/record->gain would not have to be changed and nor would scripts that want 
 to set the hw gain via audioctl(1) and don't specify the -p swich have to be 
 changed.
 
 
 Best regards,
 
 Nat
 
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 Index: audio.c
 ===================================================================
 RCS file: /cvsroot/src/sys/dev/audio.c,v
 retrieving revision 1.456
 diff -u -p -r1.456 audio.c
 --- audio.c	17 May 2018 11:35:31 -0000	1.456
 +++ audio.c	20 May 2018 10:07:09 -0000
 @@ -234,6 +234,8 @@ int	audiosetinfo(struct audio_softc *, s
  int	audiogetinfo(struct audio_softc *, struct audio_info *, int,
  		     struct virtual_channel *);
  
 +int	audioctl_open(dev_t, struct audio_softc *, int, int, struct lwp *,
 +		   struct file **);
  int	audio_open(dev_t, struct audio_softc *, int, int, struct lwp *,
  		   struct file **);
  int	audio_close(struct audio_softc *, int, struct audio_chan *);
 @@ -1678,9 +1680,11 @@ audioopen(dev_t dev, int flags, int ifmt
  	switch (AUDIODEV(dev)) {
  	case SOUND_DEVICE:
  	case AUDIO_DEVICE:
 -	case AUDIOCTL_DEVICE:
  		error = audio_open(dev, sc, flags, ifmt, l, &fp);
  		break;
 +	case AUDIOCTL_DEVICE:
 +		error = audioctl_open(dev, sc, flags, ifmt, l, &fp);
 +		break;
  	case MIXER_DEVICE:
  		error = mixer_open(dev, sc, flags, ifmt, l, &fp);
  		break;
 @@ -1714,9 +1718,11 @@ audioclose(struct file *fp)
  	switch (AUDIODEV(dev)) {
  	case SOUND_DEVICE:
  	case AUDIO_DEVICE:
 -	case AUDIOCTL_DEVICE:
  		error = audio_close(sc, fp->f_flag, chan);
  		break;
 +	case AUDIOCTL_DEVICE:
 +		error = 0;
 +		break;
  	case MIXER_DEVICE:
  		error = mixer_close(sc, fp->f_flag, chan);
  		break;
 @@ -2144,6 +2150,50 @@ audio_calcwater(struct audio_softc *sc, 
  }
  
  int
 +audioctl_open(dev_t dev, struct audio_softc *sc, int flags, int ifmt,
 +    struct lwp *l, struct file **nfp)
 +{
 +	struct file *fp;
 +	int error, fd;
 +	const struct audio_hw_if *hw;
 +	struct virtual_channel *vc;
 +	struct audio_chan *chan;
 +
 +	KASSERT(mutex_owned(sc->sc_lock));
 +
 +	if (sc->sc_usemixer && !sc->sc_ready)
 +		return ENXIO;
 +
 +	hw = sc->hw_if;
 +	if (hw == NULL)
 +		return ENXIO;
 +
 +	chan = kmem_zalloc(sizeof(struct audio_chan), KM_SLEEP);
 +	if (sc->sc_usemixer)
 +		vc = &sc->sc_mixring;
 +	else
 +		vc = sc->sc_hwvc;
 +	chan->vc = vc;
 +
 +	error = fd_allocfile(&fp, &fd);
 +	if (error)
 +		goto bad;
 +
 +	chan->dev = dev;
 +	chan->chan = 0;
 +	chan->deschan = 0;
 +
 +	error = fd_clone(fp, fd, flags, &audio_fileops, chan);
 +	KASSERT(error == EMOVEFD);
 +
 +	*nfp = fp;
 +	return error;
 +bad:
 +	kmem_free(chan, sizeof(struct audio_chan));
 +	return error;
 +}
 +
 +int
  audio_open(dev_t dev, struct audio_softc *sc, int flags, int ifmt,
      struct lwp *l, struct file **nfp)
  {
 @@ -2175,9 +2225,6 @@ audio_open(dev_t dev, struct audio_softc
  		vc = sc->sc_hwvc;
  	chan->vc = vc;
  
 -	if (!sc->sc_usemixer && AUDIODEV(dev) == AUDIOCTL_DEVICE)
 -		goto audioctl_dev;
 -
  	if (sc->sc_usemixer) {
  		vc->sc_open = 0;
  		vc->sc_mode = 0;
 @@ -2295,12 +2342,9 @@ audio_open(dev_t dev, struct audio_softc
  	/* audio_close() decreases sc_mpr[n].usedlow, recalculate here */
  	audio_calcwater(sc, vc);
  
 -audioctl_dev:
  	error = fd_allocfile(&fp, &fd);
  	if (error)
  		goto bad;
 -	if (!sc->sc_usemixer && AUDIODEV(dev) == AUDIOCTL_DEVICE)
 -		goto setup_chan;
  
  	DPRINTF(("audio_open: done sc_mode = 0x%x\n", vc->sc_mode));
  
 @@ -2311,7 +2355,6 @@ audioctl_dev:
  	if (flags & FWRITE)
  		sc->sc_opens++;
  
 -setup_chan:
  	chan->dev = dev;
  	chan->chan = n;
  	chan->deschan = n;
 @@ -2488,9 +2531,6 @@ audio_close(struct audio_softc *sc, int 
  
  	KASSERT(mutex_owned(sc->sc_lock));
  	
 -	if (!sc->sc_usemixer && AUDIODEV(chan->dev) == AUDIOCTL_DEVICE)
 -		return 0;
 -
  	if (sc->sc_opens == 0 && sc->sc_recopens == 0)
  		return ENXIO;
  
 
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