ALSA: hda - Add a fake mute feature

Some codecs don't supply the mute amp-capabilities although the lowest
volume gives the mute.  It'd be handy if the parser provides the mute
mixers in such a case.

This patch adds an extension amp-cap bit (which is used only in the
driver) to represent the min volume = mute state.  Also modified the
amp cache code to support the fake mute feature when this bit is set
but the real mute bit is unset.

In addition, conexant cx5051 parser uses this new feature to implement
the missing mute controls.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42825

Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.c

@@ -1759,7 +1759,11 @@ static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
 	parm = ch ? AC_AMP_SET_RIGHT : AC_AMP_SET_LEFT;
 	parm |= direction == HDA_OUTPUT ? AC_AMP_SET_OUTPUT : AC_AMP_SET_INPUT;
 	parm |= index << AC_AMP_SET_INDEX_SHIFT;
-	parm |= val;
+	if ((val & HDA_AMP_MUTE) && !(info->amp_caps & AC_AMPCAP_MUTE) &&
+	    (info->amp_caps & AC_AMPCAP_MIN_MUTE))
+		; /* set the zero value as a fake mute */
+	else
+		parm |= val;
 	snd_hda_codec_write(codec, nid, 0, AC_VERB_SET_AMP_GAIN_MUTE, parm);
 	info->vol[ch] = val;
 }
@@ -2026,7 +2030,7 @@ int snd_hda_mixer_amp_tlv(struct snd_kcontrol *kcontrol, int op_flag,
 	val1 = -((caps & AC_AMPCAP_OFFSET) >> AC_AMPCAP_OFFSET_SHIFT);
 	val1 += ofs;
 	val1 = ((int)val1) * ((int)val2);
-	if (min_mute)
+	if (min_mute || (caps & AC_AMPCAP_MIN_MUTE))
 		val2 |= TLV_DB_SCALE_MUTE;
 	if (put_user(SNDRV_CTL_TLVT_DB_SCALE, _tlv))
 		return -EFAULT;

sound/pci/hda/hda_codec.h

@@ -298,6 +298,9 @@ enum {
 #define AC_AMPCAP_MUTE			(1<<31)    /* mute capable */
 #define AC_AMPCAP_MUTE_SHIFT		31
 
+/* driver-specific amp-caps: using bits 24-30 */
+#define AC_AMPCAP_MIN_MUTE		(1 << 30) /* min-volume = mute */
+
 /* Connection list */
 #define AC_CLIST_LENGTH			(0x7f<<0)
 #define AC_CLIST_LONG			(1<<7)

sound/pci/hda/patch_conexant.c

@@ -4079,7 +4079,8 @@ static int cx_auto_add_volume_idx(struct hda_codec *codec, const char *basename,
 		err = snd_hda_ctl_add(codec, nid, kctl);
 		if (err < 0)
 			return err;
-		if (!(query_amp_caps(codec, nid, hda_dir) & AC_AMPCAP_MUTE))
+		if (!(query_amp_caps(codec, nid, hda_dir) &
+		      (AC_AMPCAP_MUTE | AC_AMPCAP_MIN_MUTE)))
 			break;
 	}
 	return 0;
@@ -4379,6 +4380,22 @@ static const struct snd_pci_quirk cxt_fixups[] = {
 	{}
 };
 
+/* add "fake" mute amp-caps to DACs on cx5051 so that mixer mute switches
+ * can be created (bko#42825)
+ */
+static void add_cx5051_fake_mutes(struct hda_codec *codec)
+{
+	static hda_nid_t out_nids[] = {
+		0x10, 0x11, 0
+	};
+	hda_nid_t *p;
+
+	for (p = out_nids; *p; p++)
+		snd_hda_override_amp_caps(codec, *p, HDA_OUTPUT,
+					  AC_AMPCAP_MIN_MUTE |
+					  query_amp_caps(codec, *p, HDA_OUTPUT));
+}
+
 static int patch_conexant_auto(struct hda_codec *codec)
 {
 	struct conexant_spec *spec;
@@ -4397,6 +4414,9 @@ static int patch_conexant_auto(struct hda_codec *codec)
 	case 0x14f15045:
 		spec->single_adc_amp = 1;
 		break;
+	case 0x14f15051:
+		add_cx5051_fake_mutes(codec);
+		break;
 	}
 
 	apply_pin_fixup(codec, cxt_fixups, cxt_pincfg_tbl);