[alsa-devel] [RFC] [Patch 1/2] Add virtual master control

[Daniel Jacobowitz]

On Sat, Mar 22, 2008 at 10:09:23AM +0100, Takashi Iwai wrote:
> At Fri, 21 Mar 2008 15:08:55 -0400,
> Daniel Jacobowitz wrote:
> > 
> > On Wed, Jan 30, 2008 at 04:27:07PM +0100, Takashi Iwai wrote:
> > > Because HD-audio is the only user, so far.  I don't want to expand the
> > > core stuff (and kconfig) unless really needed.
> > 
> > I said I'd want this for ice1724 / vt1616, and I finally got time to
> > do it.  What do you think of this patch?  I'm happily using it.
> 
> Well, don't forget to check HG version before you submit a patch :)

Whoops!  This version works with the hg tree.  The new
snd_ac97_add_vmaster is mostly similar to the hda version so it might
make sense to put that in vmaster.c instead.

From: Daniel Jacobowitz <dan at codesourcery.com>

Enable VMASTER for VT1616 / VT1617A.

Signed-off-by: Daniel Jacobowitz <dan at codesourcery.com>

diff -r 0d5f43585ca7 drivers/Kconfig
--- a/drivers/Kconfig	Sat Mar 22 10:26:05 2008 +0100
+++ b/drivers/Kconfig	Sat Mar 22 11:02:16 2008 -0400
@@ -44,6 +44,7 @@ config SND_AC97_CODEC
 	tristate
 	select SND_PCM
 	select AC97_BUS
+	select SND_VMASTER
 
 config SND_DUMMY
 	tristate "Dummy (/dev/null) soundcard"
diff -r 0d5f43585ca7 pci/ac97/ac97_patch.c
--- a/pci/ac97/ac97_patch.c	Sat Mar 22 10:26:05 2008 +0100
+++ b/pci/ac97/ac97_patch.c	Sat Mar 22 11:02:16 2008 -0400
@@ -3332,8 +3332,66 @@ AC97_SINGLE("Downmix Surround to Front",
 AC97_SINGLE("Downmix Surround to Front", 0x5a, 11, 1, 0),
 };
 
+static const char *slave_vols_vt1616[] = {
+	"Front Playback Volume",
+	"Surround Playback Volume",
+	"Center Playback Volume",
+	"LFE Playback Volume",
+	NULL
+};
+
+static const char *slave_sws_vt1616[] = {
+	"Front Playback Switch",
+	"Surround Playback Switch",
+	"Center Playback Switch",
+	"LFE Playback Switch",
+	NULL
+};
+
+/* find a mixer control element with the given name */
+static struct snd_kcontrol *snd_ac97_find_mixer_ctl(struct snd_ac97 *ac97,
+						    const char *name)
+{
+	struct snd_ctl_elem_id id;
+	memset(&id, 0, sizeof(id));
+	id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
+	strcpy(id.name, name);
+	return snd_ctl_find_id(ac97->bus->card, &id);
+}
+
+/* create a virtual master control and add slaves */
+int snd_ac97_add_vmaster(struct snd_ac97 *ac97, char *name,
+			 const unsigned int *tlv, const char **slaves)
+{
+	struct snd_kcontrol *kctl;
+	const char **s;
+	int err;
+
+	kctl = snd_ctl_make_virtual_master(name, tlv);
+	if (!kctl)
+		return -ENOMEM;
+	err = snd_ctl_add(ac97->bus->card, kctl);
+	if (err < 0)
+		return err;
+	
+	for (s = slaves; *s; s++) {
+		struct snd_kcontrol *sctl;
+
+		sctl = snd_ac97_find_mixer_ctl(ac97, *s);
+		if (!sctl) {
+			snd_printdd("Cannot find slave %s, skipped\n", *s);
+			continue;
+		}
+		err = snd_ctl_add_slave(kctl, sctl);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
 static int patch_vt1616_specific(struct snd_ac97 * ac97)
 {
+	struct snd_kcontrol *kctl;
 	int err;
 
 	if (snd_ac97_try_bit(ac97, 0x5a, 9))
@@ -3341,6 +3399,24 @@ static int patch_vt1616_specific(struct 
 			return err;
 	if ((err = patch_build_controls(ac97, &snd_ac97_controls_vt1616[1], ARRAY_SIZE(snd_ac97_controls_vt1616) - 1)) < 0)
 		return err;
+
+	/* There is already a misnamed master switch.  Rename it.  */
+	kctl = snd_ac97_find_mixer_ctl(ac97, "Master Playback Volume");
+	if (!kctl)
+		return -EINVAL;
+
+	snd_ac97_rename_vol_ctl(ac97, "Master Playback", "Front Playback");
+
+	err = snd_ac97_add_vmaster(ac97, "Master Playback Volume",
+				   kctl->tlv.p, slave_vols_vt1616);
+	if (err < 0)
+		return err;
+
+	err = snd_ac97_add_vmaster(ac97, "Master Playback Switch",
+				   NULL, slave_sws_vt1616);
+	if (err < 0)
+		return err;
+
 	return 0;
 }
 

-- 
Daniel Jacobowitz
CodeSourcery