sound: via82xx: move DXS volume controls to PCM interface

The "VIA DXS" controls are actually volume controls that apply to the
four PCM substreams, so we better indicate this connection by moving the
controls to the PCM interface.

Commit b452e08e73c0e3dbb0be82130217be4b7084299e in 2.6.30 broke the
restoring of these volumes by "alsactl restore" that most distributions
use; the renaming in this patch cures that regression by preventing
alsactl from applying the old, wrong volume levels to the new controls.
http://bugzilla.kernel.org/show_bug.cgi?id=14151
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=532613

Signed-off-by: Clemens Ladisch <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

sound/pci/via82xx.c

···
 				      struct snd_ctl_elem_value *ucontrol)
 {
 	struct via82xx *chip = snd_kcontrol_chip(kcontrol);
-	unsigned int idx = snd_ctl_get_ioff(kcontrol, &ucontrol->id);
+	unsigned int idx = kcontrol->id.subdevice;
 
 	ucontrol->value.integer.value[0] = VIA_DXS_MAX_VOLUME - chip->playback_volume[idx][0];
 	ucontrol->value.integer.value[1] = VIA_DXS_MAX_VOLUME - chip->playback_volume[idx][1];
···
 				      struct snd_ctl_elem_value *ucontrol)
 {
 	struct via82xx *chip = snd_kcontrol_chip(kcontrol);
-	unsigned int idx = snd_ctl_get_ioff(kcontrol, &ucontrol->id);
+	unsigned int idx = kcontrol->id.subdevice;
 	unsigned long port = chip->port + 0x10 * idx;
 	unsigned char val;
 	int i, change = 0;
···
 };
 
 static struct snd_kcontrol_new snd_via8233_dxs_volume_control __devinitdata = {
-	.name = "VIA DXS Playback Volume",
-	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+	.device = 0,
+	/* .subdevice set later */
+	.name = "PCM Playback Volume",
 	.access = (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 		   SNDRV_CTL_ELEM_ACCESS_TLV_READ),
-	.count = 4,
 	.info = snd_via8233_dxs_volume_info,
 	.get = snd_via8233_dxs_volume_get,
 	.put = snd_via8233_dxs_volume_put,
···
 		}
 		else /* Using DXS when PCM emulation is enabled is really weird */
 		{
-			/* Standalone DXS controls */
-			err = snd_ctl_add(chip->card, snd_ctl_new1(&snd_via8233_dxs_volume_control, chip));
-			if (err < 0)
-				return err;
+			for (i = 0; i < 4; ++i) {
+				struct snd_kcontrol *kctl;
+
+				kctl = snd_ctl_new1(
+					&snd_via8233_dxs_volume_control, chip);
+				if (!kctl)
+					return -ENOMEM;
+				kctl->id.subdevice = i;
+				err = snd_ctl_add(chip->card, kctl);
+				if (err < 0)
+					return err;
+			}
 		}
 	}
 	/* select spdif data slot 10/11 */