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>
diff --git a/sound/pci/hda/patch_conexant.c b/sound/pci/hda/patch_conexant.c
index a7a5733..ca117cf 100644
--- a/sound/pci/hda/patch_conexant.c
+++ b/sound/pci/hda/patch_conexant.c
@@ -4079,7 +4079,8 @@
 		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 @@
 	{}
 };
 
+/* 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 @@
 	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);