[3.19.y-ckt stable] Patch "ALSA: usb-audio: Fix runtime PM unbalance" 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: usb-audio: Fix runtime PM unbalance

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt7.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From bdbacdb48e2dc27290c0456cfd20381b5109fbb1 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai at suse.de>
Date: Wed, 19 Aug 2015 07:20:14 +0200
Subject: ALSA: usb-audio: Fix runtime PM unbalance

commit 9003ebb13f61e8c78a641e0dda7775183ada0625 upstream.

The fix for deadlock in PM in commit [1ee23fe07ee8: ALSA: usb-audio:
Fix deadlocks at resuming] introduced a new check of in_pm flag.
However, the brainless patch author evaluated it in a wrong way
(logical AND instead of logical OR), thus usb_autopm_get_interface()
is wrongly called at probing, leading to unbalance of runtime PM
refcount.

This patch fixes it by correcting the logic.

Reported-by: Hans Yang <hansy at nvidia.com>
Fixes: 1ee23fe07ee8 ('ALSA: usb-audio: Fix deadlocks at resuming')
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 sound/usb/card.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1fab977..0450593 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -638,7 +638,7 @@ int snd_usb_autoresume(struct snd_usb_audio *chip)
 	int err = -ENODEV;

 	down_read(&chip->shutdown_rwsem);
-	if (chip->probing && chip->in_pm)
+	if (chip->probing || chip->in_pm)
 		err = 0;
 	else if (!chip->shutdown)
 		err = usb_autopm_get_interface(chip->pm_intf);
--
1.9.1