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

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

Hi, 

On Sun, 20 May 2018 17:27:17 matthew green wrote:
> play.gain is the traditional way the "sun audio" interface has
> worked, so any other tool that thought this was a master volume
> (which it has been, until recently) has to be updated, whether
> it is a C program or a script.

I believe this is the way to go, but it's possibly too soon for those with 
existing software.

> 
> that's not particularly nice for the end users, so i would like
> to at least restore the original functionality if there is one
> vchan only, if not more generally.
> 

How about the attached patch it will set the hw gain also if their is only one 
channel open (recording or playback).  If this is good I'll document this 
behaviour and update the spec.

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 08:44:55 -0000
@@ -4755,27 +4755,32 @@ done:
 			goto cleanup;
 	}
 	if (SPECIFIED(p->gain)) {
-		if (!sc->sc_usemixer || vc == &sc->sc_mixring) {
+		if (sc->sc_opens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_outports, &gain, &balance);
 			error = au_set_gain(sc, &sc->sc_outports, p->gain, balance);
 			if (error)
 				goto cleanup;
-		} else
+		}
+		if (sc->sc_usemixer)
 			vc->sc_swvol = p->gain;
 	}
 
 	if (SPECIFIED(r->gain)) {
-		if (!sc->sc_usemixer || vc == &sc->sc_mixring) {
+		if (sc->sc_recopens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_inports, &gain, &balance);
 			error = au_set_gain(sc, &sc->sc_inports, r->gain, balance);
 			if (error)
 				goto cleanup;
-		} else
+		}
+		if (sc->sc_usemixer)
 			vc->sc_recswvol = r->gain;
 	}
 
 	if (SPECIFIED_CH(p->balance)) {
-		if (!sc->sc_usemixer || vc == &sc->sc_mixring) {
+		if (sc->sc_opens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_outports, &gain, &balance);
 			error = au_set_gain(sc, &sc->sc_outports, gain, p->balance);
 			if (error)
@@ -4783,7 +4788,8 @@ done:
 		}
 	}
 	if (SPECIFIED_CH(r->balance)) {
-		if (!sc->sc_usemixer || vc == &sc->sc_mixring) {
+		if (sc->sc_recopens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_inports, &gain, &balance);
 			error = au_set_gain(sc, &sc->sc_inports, gain, r->balance);
 			if (error)
@@ -4932,13 +4938,17 @@ audiogetinfo(struct audio_softc *sc, str
 		r->avail_ports = sc->sc_inports.allports;
 		p->avail_ports = sc->sc_outports.allports;
 
-		if (!sc->sc_usemixer || vc == &sc->sc_mixring) {
+		if (sc->sc_recopens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_inports, &r->gain, &r->balance);
+		} else
+			r->gain = vc->sc_recswvol;
+
+		if (sc->sc_opens == 1 || !sc->sc_usemixer ||
+						 vc == &sc->sc_mixring) {
 			au_get_gain(sc, &sc->sc_outports, &p->gain, &p->balance);
-		} else {
+		} else
 			p->gain = vc->sc_swvol;
-			r->gain = vc->sc_recswvol;
-		}
 	}
 
 	if (sc->sc_monitor_port != -1 && buf_only_mode == 0) {