From patchwork Thu Nov 15 05:49:02 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [3.5.yuz, extended, stable] Patch "ALSA: hda - Fix hang caused by race during suspend." has been added to staging queue Date: Wed, 14 Nov 2012 19:49:02 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 199163 Message-Id: <1352958542-16421-1-git-send-email-herton.krzesinski@canonical.com> To: Dylan Reid Cc: Takashi Iwai , kernel-team@lists.ubuntu.com This is a note to let you know that I have just added a patch titled ALSA: hda - Fix hang caused by race during suspend. to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ >From fea3a15a30517e7de8048c64338d90316bd7b350 Mon Sep 17 00:00:00 2001 From: Dylan Reid Date: Fri, 28 Sep 2012 15:57:01 -0700 Subject: [PATCH] ALSA: hda - Fix hang caused by race during suspend. commit d17344b3547669f5b6ee4fda993d03737a141bd6 upstream. There was a race condition when the system suspends while hda_power_work is running in the work queue. If system suspend (snd_hda_suspend) happens after the work queue releases power_lock but before it calls hda_call_codec_suspend, codec_suspend runs with power_on=0, causing the codec to power up for register reads, and hanging when it calls cancel_delayed_work_sync from the running work queue. The call chain from the work queue will look like this: hda_power_work <<- power_on = 1, unlock, then power_on cleard by suspend hda_call_codec_suspend hda_set_power_state snd_hda_codec_read codec_exec_verb snd_hda_power_up snd_hda_power_save __snd_hda_power_up cancel_delayed_work_sync <<-- cancelling executing wq Fix this by waiting for the work queue to finish before starting suspend if suspend is not happening on the work queue. Signed-off-by: Dylan Reid Signed-off-by: Takashi Iwai [ herton: backported to 3.5: * hda_call_codec_suspend doesn't return state * adjusted context ] Signed-off-by: Herton Ronaldo Krzesinski --- sound/pci/hda/hda_codec.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) -- 1.7.9.5 diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c index f1c6164..b1b6238 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -3542,7 +3542,7 @@ static inline void hda_exec_init_verbs(struct hda_codec *codec) {} /* * call suspend and power-down; used both from PM and power-save */ -static void hda_call_codec_suspend(struct hda_codec *codec) +static void hda_call_codec_suspend(struct hda_codec *codec, bool in_wq) { if (codec->patch_ops.suspend) codec->patch_ops.suspend(codec, PMSG_SUSPEND); @@ -3551,7 +3551,9 @@ static void hda_call_codec_suspend(struct hda_codec *codec) codec->afg ? codec->afg : codec->mfg, AC_PWRST_D3); #ifdef CONFIG_SND_HDA_POWER_SAVE - cancel_delayed_work(&codec->power_work); + /* Cancel delayed work if we aren't currently running from it. */ + if (!in_wq) + cancel_delayed_work_sync(&codec->power_work); spin_lock(&codec->power_lock); snd_hda_update_power_acct(codec); trace_hda_power_down(codec); @@ -4372,7 +4374,7 @@ static void hda_power_work(struct work_struct *work) } spin_unlock(&codec->power_lock); - hda_call_codec_suspend(codec); + hda_call_codec_suspend(codec, true); if (bus->ops.pm_notify) bus->ops.pm_notify(bus); } @@ -5038,7 +5040,7 @@ int snd_hda_suspend(struct hda_bus *bus) list_for_each_entry(codec, &bus->codec_list, list) { if (hda_codec_is_power_on(codec)) - hda_call_codec_suspend(codec); + hda_call_codec_suspend(codec, false); } return 0; }