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>

1 files changed, 6 insertions, 2 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index c2c65f63bf06..0ae6eb20b13b 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/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;