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

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

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

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;