[3.13.y-ckt stable] Patch "ALSA: hda - Don't access stereo amps for mono channel widgets" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ALSA: hda - Don't access stereo amps for mono channel widgets

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt19.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 71425cc66b0aedf8d3ad0aa1a08483c5f03fff9e Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai at suse.de>
Date: Thu, 12 Mar 2015 08:30:11 +0100
Subject: ALSA: hda - Don't access stereo amps for mono channel widgets

commit ef403edb75580a3ec5d155f5de82155f0419c621 upstream.

The current HDA generic parser initializes / modifies the amp values
always in stereo, but this seems causing the problem on ALC3229 codec
that has a few mono channel widgets: namely, these mono widgets react
to actions for both channels equally.

In the driver code, we do care the mono channel and create a control
only for the left channel (as defined in HD-audio spec) for such a
node.  When the control is updated, only the left channel value is
changed.  However, in the resume, the right channel value is also
restored from the initial value we took as stereo, and this overwrites
the left channel value.  This ends up being the silent output as the
right channel has been never touched and remains muted.

This patch covers the places where unconditional stereo amp accesses
are done and converts to the conditional accesses.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94581
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 sound/pci/hda/hda_generic.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index 7d4ccfa..9c7cd6c 100644
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -657,7 +657,23 @@ static void init_amp(struct hda_codec *codec, hda_nid_t nid, int dir, int idx)
 {
 	unsigned int caps = query_amp_caps(codec, nid, dir);
 	int val = get_amp_val_to_activate(codec, nid, dir, caps, false);
-	snd_hda_codec_amp_init_stereo(codec, nid, dir, idx, 0xff, val);
+
+	if (get_wcaps(codec, nid) & AC_WCAP_STEREO)
+		snd_hda_codec_amp_init_stereo(codec, nid, dir, idx, 0xff, val);
+	else
+		snd_hda_codec_amp_init(codec, nid, 0, dir, idx, 0xff, val);
+}
+
+/* update the amp, doing in stereo or mono depending on NID */
+static int update_amp(struct hda_codec *codec, hda_nid_t nid, int dir, int idx,
+		      unsigned int mask, unsigned int val)
+{
+	if (get_wcaps(codec, nid) & AC_WCAP_STEREO)
+		return snd_hda_codec_amp_stereo(codec, nid, dir, idx,
+						mask, val);
+	else
+		return snd_hda_codec_amp_update(codec, nid, 0, dir, idx,
+						mask, val);
 }

 /* calculate amp value mask we can modify;
@@ -697,7 +713,7 @@ static void activate_amp(struct hda_codec *codec, hda_nid_t nid, int dir,
 		return;

 	val &= mask;
-	snd_hda_codec_amp_stereo(codec, nid, dir, idx, mask, val);
+	update_amp(codec, nid, dir, idx, mask, val);
 }

 static void activate_amp_out(struct hda_codec *codec, struct nid_path *path,
@@ -4331,13 +4347,11 @@ static void mute_all_mixer_nid(struct hda_codec *codec, hda_nid_t mix)
 	has_amp = nid_has_mute(codec, mix, HDA_INPUT);
 	for (i = 0; i < nums; i++) {
 		if (has_amp)
-			snd_hda_codec_amp_stereo(codec, mix,
-						 HDA_INPUT, i,
-						 0xff, HDA_AMP_MUTE);
+			update_amp(codec, mix, HDA_INPUT, i,
+				   0xff, HDA_AMP_MUTE);
 		else if (nid_has_volume(codec, conn[i], HDA_OUTPUT))
-			snd_hda_codec_amp_stereo(codec, conn[i],
-						 HDA_OUTPUT, 0,
-						 0xff, HDA_AMP_MUTE);
+			update_amp(codec, conn[i], HDA_OUTPUT, 0,
+				   0xff, HDA_AMP_MUTE);
 	}
 }

--
1.9.1