[alsa-devel] [RFC] [Patch 2/2] Add virtual master to HD-audio

20 Dec 2007

This patch adds the virtual master controls to some codecs.
The virtual master controls are added only when no real "Master"
control is present.
Takashi
diff -r 861c951ac951 pci/Kconfig

--- a/pci/Kconfig	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/Kconfig	Tue Sep 18 15:48:29 2007 +0200
@@ -512,6 +512,7 @@ config SND_HDA_CODEC_REALTEK
 config SND_HDA_CODEC_REALTEK
    bool "Build Realtek HD-audio codec support"
    depends on SND_HDA_INTEL
+	select SND_VMASTER
    default y
    help
      Say Y here to include Realtek HD-audio codec support in
@@ -520,6 +521,7 @@ config SND_HDA_CODEC_ANALOG
 config SND_HDA_CODEC_ANALOG
    bool "Build Analog Device HD-audio codec support"
    depends on SND_HDA_INTEL
+	select SND_VMASTER
    default y
    help
      Say Y here to include Analog Device HD-audio codec support in
@@ -528,6 +530,7 @@ config SND_HDA_CODEC_SIGMATEL
 config SND_HDA_CODEC_SIGMATEL
    bool "Build IDT/Sigmatel HD-audio codec support"
    depends on SND_HDA_INTEL
+	select SND_VMASTER
    default y
    help
      Say Y here to include IDT (Sigmatel) HD-audio codec support in
diff -r 861c951ac951 pci/hda/hda_codec.c
--- a/pci/hda/hda_codec.c	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/hda/hda_codec.c	Tue Sep 18 15:48:29 2007 +0200
@@ -1016,6 +1016,68 @@ int snd_hda_mixer_amp_tlv(struct snd_kco
    	return -EFAULT;
    return 0;
 }
+
+#ifdef CONFIG_SND_VMASTER
+/*
+ * set (static) TLV for virtual master volume; recalculated as max 0dB
+ */
+void snd_hda_set_vmaster_tlv(struct hda_codec *codec, hda_nid_t nid, int dir,
+			     unsigned int *tlv)
+{
+	u32 caps;
+	int nums, step;
+
+	caps = query_amp_caps(codec, nid, dir);
+	nums = (caps & AC_AMPCAP_NUM_STEPS) >> AC_AMPCAP_NUM_STEPS_SHIFT;
+	step = (caps & AC_AMPCAP_STEP_SIZE) >> AC_AMPCAP_STEP_SIZE_SHIFT;
+	step = (step + 1) * 25;
+	tlv[0] = SNDRV_CTL_TLVT_DB_SCALE;
+	tlv[1] = 2 * sizeof(unsigned int);
+	tlv[2] = -nums * step;
+	tlv[3] = step;
+}
+
+/* find a mixer control element with the given name */
+struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,
+					    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(codec->bus->card, &id);
+}
+
+/* create a virtual master control and add slaves */
+int snd_hda_add_vmaster(struct hda_codec *codec, char *name,
+			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(codec->bus->card, kctl);
+	if (err < 0)
+		return err;
+	
+	for (s = slaves; *s; s++) {
+		struct snd_kcontrol *sctl;
+
+		sctl = snd_hda_find_mixer_ctl(codec, *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;
+}
+#endif /* CONFIG_SND_VMASTER */
/* switch */
 int snd_hda_mixer_amp_switch_info(struct snd_kcontrol *kcontrol,
diff -r 861c951ac951 pci/hda/hda_local.h
--- a/pci/hda/hda_local.h	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/hda/hda_local.h	Tue Sep 18 15:48:29 2007 +0200
@@ -90,6 +90,13 @@ void snd_hda_codec_resume_amp(struct hda
 void snd_hda_codec_resume_amp(struct hda_codec *codec);
 #endif
+void snd_hda_set_vmaster_tlv(struct hda_codec *codec, hda_nid_t nid, int dir,
+			     unsigned int *tlv);
+struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,
+					    const char *name);
+int snd_hda_add_vmaster(struct hda_codec *codec, char *name,
+			unsigned int *tlv, const char **slaves);
+
 /* amp value bits */
 #define HDA_AMP_MUTE	0x80
 #define HDA_AMP_UNMUTE	0x00
diff -r 861c951ac951 pci/hda/patch_analog.c
--- a/pci/hda/patch_analog.c	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/hda/patch_analog.c	Tue Sep 18 15:48:29 2007 +0200
@@ -79,6 +79,11 @@ struct ad198x_spec {
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    struct hda_loopback_check loopback;
 #endif
+	/* for virtual master */
+	hda_nid_t vmaster_nid;
+	u32 vmaster_tlv[4];
+	const char **slave_vols;
+	const char **slave_sws;
 };
/*
@@ -125,6 +130,28 @@ static int ad198x_init(struct hda_codec 
    	snd_hda_sequence_write(codec, spec->init_verbs[i]);
    return 0;
 }
+
+static const char *ad_slave_vols[] = {
+	"Front Playback Volume",
+	"Surround Playback Volume",
+	"Center Playback Volume",
+	"LFE Playback Volume",
+	"Side Playback Volume",
+	"Headphone Playback Volume",
+	"Mono Playback Volume",
+	NULL
+};
+
+static const char *ad_slave_sws[] = {
+	"Front Playback Switch",
+	"Surround Playback Switch",
+	"Center Playback Switch",
+	"LFE Playback Switch",
+	"Side Playback Switch",
+	"Headphone Playback Switch",
+	"Mono Playback Switch",
+	NULL
+};
static int ad198x_build_controls(struct hda_codec *codec)
 {
@@ -147,6 +174,27 @@ static int ad198x_build_controls(struct 
    	if (err < 0)
    		return err;
    }
+
+	/* if we have no master control, let's create it */
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Volume")) {
+		snd_hda_set_vmaster_tlv(codec, spec->vmaster_nid,
+					HDA_OUTPUT, spec->vmaster_tlv);
+		err = snd_hda_add_vmaster(codec, "Master Playback Volume",
+					  spec->vmaster_tlv,
+					  (spec->slave_vols ?
+					   spec->slave_vols : ad_slave_vols));
+		if (err < 0)
+			return err;
+	}
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Switch")) {
+		err = snd_hda_add_vmaster(codec, "Master Playback Switch",
+					  NULL,
+					  (spec->slave_sws ?
+					   spec->slave_sws : ad_slave_sws));
+		if (err < 0)
+			return err;
+	}
+
    return 0;
 }
@@ -897,6 +945,7 @@ static int patch_ad1986a(struct hda_code
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1986a_loopbacks;
 #endif
+	spec->vmaster_nid = 0x1b;
codec->patch_ops = ad198x_patch_ops;
@@ -1129,6 +1178,7 @@ static int patch_ad1983(struct hda_codec
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1983_loopbacks;
 #endif
+	spec->vmaster_nid = 0x05;
codec->patch_ops = ad198x_patch_ops;
@@ -1525,6 +1575,7 @@ static int patch_ad1981(struct hda_codec
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1981_loopbacks;
 #endif
+	spec->vmaster_nid = 0x05;
codec->patch_ops = ad198x_patch_ops;
@@ -2834,6 +2885,7 @@ static int patch_ad1988(struct hda_codec
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1988_loopbacks;
 #endif
+	spec->vmaster_nid = 0x04;
return 0;
 }
@@ -3000,6 +3052,19 @@ static struct hda_amp_list ad1884_loopba
 };
 #endif
+static const char *ad1884_slave_vols[] = {
+	"PCM Playback Volume",
+	"Mic Playback Volume",
+	"Mono Playback Volume",
+	"Front Mic Playback Volume",
+	"Mic Playback Volume",
+	"CD Playback Volume",
+	"Internal Mic Playback Volume",
+	"Docking Mic Playback Volume"
+	"Beep Playback Volume",
+	NULL
+};
+
 static int patch_ad1884(struct hda_codec *codec)
 {
    struct ad198x_spec *spec;
@@ -3027,6 +3092,9 @@ static int patch_ad1884(struct hda_codec
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1884_loopbacks;
 #endif
+	spec->vmaster_nid = 0x04;
+	/* we need to cover all playback volumes */
+	spec->slave_vols = ad1884_slave_vols;
codec->patch_ops = ad198x_patch_ops;
@@ -3459,6 +3527,7 @@ static int patch_ad1882(struct hda_codec
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    spec->loopback.amplist = ad1882_loopbacks;
 #endif
+	spec->vmaster_nid = 0x04;
codec->patch_ops = ad198x_patch_ops;
diff -r 861c951ac951 pci/hda/patch_realtek.c
--- a/pci/hda/patch_realtek.c	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/hda/patch_realtek.c	Tue Sep 18 15:48:29 2007 +0200
@@ -247,6 +247,9 @@ struct alc_spec {
    unsigned int sense_updated: 1;
    unsigned int jack_present: 1;
+	/* for virtual master */
+	hda_nid_t vmaster_nid;
+	u32 vmaster_tlv[4];
 #ifdef CONFIG_SND_HDA_POWER_SAVE
    struct hda_loopback_check loopback;
 #endif
@@ -1098,8 +1101,8 @@ static struct snd_kcontrol_new alc880_f1
 static struct snd_kcontrol_new alc880_f1734_mixer[] = {
    HDA_CODEC_VOLUME("Headphone Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
    HDA_BIND_MUTE("Headphone Playback Switch", 0x0c, 2, HDA_INPUT),
-	HDA_CODEC_VOLUME("Internal Speaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("Internal Speaker Playback Switch", 0x0d, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Speaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Speaker Playback Switch", 0x0d, 2, HDA_INPUT),
    HDA_CODEC_VOLUME("CD Playback Volume", 0x0b, 0x04, HDA_INPUT),
    HDA_CODEC_MUTE("CD Playback Switch", 0x0b, 0x04, HDA_INPUT),
    HDA_CODEC_VOLUME("Mic Playback Volume", 0x0b, 0x0, HDA_INPUT),
@@ -1197,10 +1200,10 @@ static struct snd_kcontrol_new alc880_tc
/* Uniwill */
 static struct snd_kcontrol_new alc880_uniwill_mixer[] = {
-	HDA_CODEC_VOLUME("HPhone Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("HPhone Playback Switch", 0x0c, 2, HDA_INPUT),
-	HDA_CODEC_VOLUME("iSpeaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("iSpeaker Playback Switch", 0x0d, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Headphone Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Headphone Playback Switch", 0x0c, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Speaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Speaker Playback Switch", 0x0d, 2, HDA_INPUT),
    HDA_CODEC_VOLUME_MONO("Center Playback Volume", 0x0e, 1, 0x0, HDA_OUTPUT),
    HDA_CODEC_VOLUME_MONO("LFE Playback Volume", 0x0e, 2, 0x0, HDA_OUTPUT),
    HDA_BIND_MUTE_MONO("Center Playback Switch", 0x0e, 1, 2, HDA_INPUT),
@@ -1240,13 +1243,47 @@ static struct snd_kcontrol_new alc880_fu
 };
static struct snd_kcontrol_new alc880_uniwill_p53_mixer[] = {
-	HDA_CODEC_VOLUME("HPhone Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("HPhone Playback Switch", 0x0c, 2, HDA_INPUT),
-	HDA_CODEC_VOLUME("iSpeaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("iSpeaker Playback Switch", 0x0d, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Headphone Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Headphone Playback Switch", 0x0c, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Speaker Playback Volume", 0x0d, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Speaker Playback Switch", 0x0d, 2, HDA_INPUT),
    HDA_CODEC_VOLUME("Mic Playback Volume", 0x0b, 0x0, HDA_INPUT),
    HDA_CODEC_MUTE("Mic Playback Switch", 0x0b, 0x0, HDA_INPUT),
    { } /* end */
+};
+
+/*
+ * virtual master controls
+ */
+
+/*
+ * slave controls for virtual master
+ */
+static const char *alc_slave_vols[] = {
+	"Front Playback Volume",
+	"Surround Playback Volume",
+	"Center Playback Volume",
+	"LFE Playback Volume",
+	"Side Playback Volume",
+	"Headphone Playback Volume",
+	"Speaker Playback Volume",
+	"Mono Playback Volume",
+	"iSpeaker Playback Volume",
+	"Line-Out Playback Volume",
+	NULL,
+};
+
+static const char *alc_slave_sws[] = {
+	"Front Playback Switch",
+	"Surround Playback Switch",
+	"Center Playback Switch",
+	"LFE Playback Switch",
+	"Side Playback Switch",
+	"Headphone Playback Switch",
+	"Speaker Playback Switch",
+	"Mono Playback Switch",
+	"iSpeaker Playback Switch",
+	NULL,
 };
/*
@@ -1275,6 +1312,23 @@ static int alc_build_controls(struct hda
    	if (err < 0)
    		return err;
    }
+
+	/* if we have no master control, let's create it */
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Volume")) {
+		snd_hda_set_vmaster_tlv(codec, spec->vmaster_nid,
+					HDA_OUTPUT, spec->vmaster_tlv);
+		err = snd_hda_add_vmaster(codec, "Master Playback Volume",
+					  spec->vmaster_tlv, alc_slave_vols);
+		if (err < 0)
+			return err;
+	}
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Switch")) {
+		err = snd_hda_add_vmaster(codec, "Master Playback Switch",
+					  NULL, alc_slave_sws);
+		if (err < 0)
+			return err;
+	}
+
    return 0;
 }
@@ -1823,8 +1877,8 @@ static struct hda_channel_mode alc880_lg
static struct snd_kcontrol_new alc880_lg_mixer[] = {
    /* FIXME: it's not really "master" but front channels */
-	HDA_CODEC_VOLUME("Master Playback Volume", 0x0f, 0x0, HDA_OUTPUT),
-	HDA_BIND_MUTE("Master Playback Switch", 0x0f, 2, HDA_INPUT),
+	HDA_CODEC_VOLUME("Front Playback Volume", 0x0f, 0x0, HDA_OUTPUT),
+	HDA_BIND_MUTE("Front Playback Switch", 0x0f, 2, HDA_INPUT),
    HDA_CODEC_VOLUME("Surround Playback Volume", 0x0c, 0x0, HDA_OUTPUT),
    HDA_BIND_MUTE("Surround Playback Switch", 0x0c, 2, HDA_INPUT),
    HDA_CODEC_VOLUME_MONO("Center Playback Volume", 0x0d, 1, 0x0, HDA_OUTPUT),
@@ -3390,6 +3444,8 @@ static int patch_alc880(struct hda_codec
    		spec->num_mixers++;
    	}
    }
+
+	spec->vmaster_nid = 0x0c;
codec->patch_ops = alc_patch_ops;
    if (board_config == ALC880_AUTO)
@@ -4762,6 +4818,8 @@ static int patch_alc260(struct hda_codec
    spec->stream_digital_playback = &alc260_pcm_digital_playback;
    spec->stream_digital_capture = &alc260_pcm_digital_capture;
+	spec->vmaster_nid = 0x08;
+
    codec->patch_ops = alc_patch_ops;
    if (board_config == ALC260_AUTO)
    	spec->init_hook = alc260_auto_init;
@@ -4962,15 +5020,15 @@ static struct snd_kcontrol_new alc882_ba
 };
static struct snd_kcontrol_new alc885_mbp3_mixer[] = {
-	HDA_CODEC_VOLUME("Master Volume", 0x0c, 0x00, HDA_OUTPUT),
-	HDA_BIND_MUTE   ("Master Switch", 0x0c, 0x02, HDA_INPUT),
-	HDA_CODEC_MUTE  ("Speaker Switch", 0x14, 0x00, HDA_OUTPUT),
-	HDA_CODEC_VOLUME("Line Out Volume", 0x0d,0x00, HDA_OUTPUT),
-	HDA_CODEC_VOLUME("Line In Playback Volume", 0x0b, 0x02, HDA_INPUT),
-	HDA_CODEC_MUTE  ("Line In Playback Switch", 0x0b, 0x02, HDA_INPUT),
+	HDA_CODEC_VOLUME("Front Playback Volume", 0x0c, 0x00, HDA_OUTPUT),
+	HDA_BIND_MUTE   ("Front Playback Switch", 0x0c, 0x02, HDA_INPUT),
+	HDA_CODEC_MUTE  ("Speaker Playback Switch", 0x14, 0x00, HDA_OUTPUT),
+	HDA_CODEC_VOLUME("Line-Out Playback Volume", 0x0d, 0x00, HDA_OUTPUT),
+	HDA_CODEC_VOLUME("Line Playback Volume", 0x0b, 0x02, HDA_INPUT),
+	HDA_CODEC_MUTE  ("Line Playback Switch", 0x0b, 0x02, HDA_INPUT),
    HDA_CODEC_VOLUME("Mic Playback Volume", 0x0b, 0x00, HDA_INPUT),
    HDA_CODEC_MUTE  ("Mic Playback Switch", 0x0b, 0x00, HDA_INPUT),
-	HDA_CODEC_VOLUME("Line In Boost", 0x1a, 0x00, HDA_INPUT),
+	HDA_CODEC_VOLUME("Line Boost", 0x1a, 0x00, HDA_INPUT),
    HDA_CODEC_VOLUME("Mic Boost", 0x18, 0x00, HDA_INPUT),
    { } /* end */
 };
@@ -5971,6 +6029,8 @@ static int patch_alc882(struct hda_codec
    		spec->num_mixers++;
    	}
    }
+
+	spec->vmaster_nid = 0x0c;
codec->patch_ops = alc_patch_ops;
    if (board_config == ALC882_AUTO)
@@ -7446,6 +7506,8 @@ static int patch_alc883(struct hda_codec
    	spec->adc_nids = alc883_adc_nids;
    	spec->num_adc_nids = ARRAY_SIZE(alc883_adc_nids);
    }
+
+	spec->vmaster_nid = 0x0c;
codec->patch_ops = alc_patch_ops;
    if (board_config == ALC883_AUTO)
@@ -8566,6 +8628,8 @@ static int patch_alc262(struct hda_codec
    	}
    }
+	spec->vmaster_nid = 0x0c;
+
    codec->patch_ops = alc_patch_ops;
    if (board_config == ALC262_AUTO)
    	spec->init_hook = alc262_auto_init;
@@ -9240,6 +9304,9 @@ static int patch_alc268(struct hda_codec
    		}
    	}
    }
+
+	spec->vmaster_nid = 0x02;
+
    codec->patch_ops = alc_patch_ops;
    if (board_config == ALC268_AUTO)
    	spec->init_hook = alc268_auto_init;
@@ -10394,6 +10461,8 @@ static int patch_alc861(struct hda_codec
    spec->stream_digital_playback = &alc861_pcm_digital_playback;
    spec->stream_digital_capture = &alc861_pcm_digital_capture;
+	spec->vmaster_nid = 0x03;
+
    codec->patch_ops = alc_patch_ops;
    if (board_config == ALC861_AUTO)
    	spec->init_hook = alc861_auto_init;
@@ -11370,6 +11439,8 @@ static int patch_alc861vd(struct hda_cod
spec->mixers[spec->num_mixers] = alc861vd_capture_mixer;
    spec->num_mixers++;
+
+	spec->vmaster_nid = 0x02;
codec->patch_ops = alc_patch_ops;
@@ -12222,6 +12293,8 @@ static int patch_alc662(struct hda_codec
    	spec->num_adc_nids = ARRAY_SIZE(alc662_adc_nids);
    }
+	spec->vmaster_nid = 0x02;
+
    codec->patch_ops = alc_patch_ops;
    if (board_config == ALC662_AUTO)
    	spec->init_hook = alc662_auto_init;
diff -r 861c951ac951 pci/hda/patch_sigmatel.c
--- a/pci/hda/patch_sigmatel.c	Tue Sep 18 15:48:16 2007 +0200
+++ b/pci/hda/patch_sigmatel.c	Tue Sep 18 15:48:29 2007 +0200
@@ -156,6 +156,9 @@ struct sigmatel_spec {
    struct snd_kcontrol_new *kctl_alloc;
    struct hda_input_mux private_dimux;
    struct hda_input_mux private_imux;
+
+	/* virtual master */
+	unsigned int vmaster_tlv[4];
 };
static hda_nid_t stac9200_adc_nids[1] = {
@@ -521,6 +524,34 @@ static struct snd_kcontrol_new stac927x_
    { } /* end */
 };
+static const char *slave_vols[] = {
+	"Front Playback Volume",
+	"Surround Playback Volume",
+	"Center Playback Volume",
+	"LFE Playback Volume",
+	"Side Playback Volume",
+	"Headphone Playback Volume",
+	"Headphone Playback Volume",
+	"Speaker Playback Volume",
+	"External Speaker Playback Volume",
+	"Speaker2 Playback Volume",
+	NULL
+};
+
+static const char *slave_sws[] = {
+	"Front Playback Switch",
+	"Surround Playback Switch",
+	"Center Playback Switch",
+	"LFE Playback Switch",
+	"Side Playback Switch",
+	"Headphone Playback Switch",
+	"Headphone Playback Switch",
+	"Speaker Playback Switch",
+	"External Speaker Playback Switch",
+	"Speaker2 Playback Switch",
+	NULL
+};
+
 static int stac92xx_build_controls(struct hda_codec *codec)
 {
    struct sigmatel_spec *spec = codec->spec;
@@ -547,6 +578,23 @@ static int stac92xx_build_controls(struc
    	if (err < 0)
    		return err;
    }
+
+	/* if we have no master control, let's create it */
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Volume")) {
+		snd_hda_set_vmaster_tlv(codec, spec->multiout.dac_nids[0],
+					HDA_OUTPUT, spec->vmaster_tlv);
+		err = snd_hda_add_vmaster(codec, "Master Playback Volume",
+					  spec->vmaster_tlv, slave_vols);
+		if (err < 0)
+			return err;
+	}
+	if (!snd_hda_find_mixer_ctl(codec, "Master Playback Switch")) {
+		err = snd_hda_add_vmaster(codec, "Master Playback Switch",
+					  NULL, slave_sws);
+		if (err < 0)
+			return err;
+	}
+
    return 0;	
 }

    

[alsa-devel] [RFC] [Patch 2/2] Add virtual master to HD-audio

Takashi Iwai