[3.8.y.z extended stable] Patch "ALSA: hda - Fix unbalanced runtime PM notification at resume" 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 - Fix unbalanced runtime PM notification at resume

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.14.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 01b428c6b9f933735d895d9d4a44121a6f3aa180 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai at suse.de>
Date: Wed, 20 Nov 2013 12:15:07 +0100
Subject: ALSA: hda - Fix unbalanced runtime PM notification at resume

commit 0fc28fc030a85aa3d6d14e9e9fca0c8237c9ffb5 upstream.

When a codec is resumed, it keeps the power on while the resuming
phase via hda_keep_power_on(), then turns down via
snd_hda_power_down().  At that point, snd_hda_power_down() notifies
the power down to the controller, and this may confuse the refcount if
the codec was already powered up before the resume.

In the end result, the controller goes to runtime suspend even before
the codec is kicked off to the power save, and the communication
stalls happens.

The fix is to add the power-up notification together with
hda_keep_power_on(), and clears the flag appropriately.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 sound/pci/hda/hda_codec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 3f242b5..b542636 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3650,6 +3650,10 @@ static void hda_call_codec_resume(struct hda_codec *codec)
 	 * in the resume / power-save sequence
 	 */
 	hda_keep_power_on(codec);
+	if (codec->pm_down_notified) {
+		codec->pm_down_notified = 0;
+		hda_call_pm_notify(codec->bus, true);
+	}
 	hda_set_power_state(codec, AC_PWRST_D0);
 	restore_shutup_pins(codec);
 	hda_exec_init_verbs(codec);
--
1.8.3.2