linux-kernel - [PATCH 3.8 142/152] ALSA: hda - Fix unbalanced runtime PM notification at resume

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Message-Id: <1386371476-2477-143-git-send-email-kamal@canonical.com>
Date:	Fri,  6 Dec 2013 15:11:06 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Takashi Iwai <tiwai@...e.de>, Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.8 142/152] ALSA: hda - Fix unbalanced runtime PM notification at resume

3.8.13.14 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@...e.de>

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@...e.de>
Signed-off-by: Kamal Mostafa <kamal@...onical.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

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