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authorDylan Reid <dgreid@chromium.org>2012-09-28 15:57:01 -0700
committerTakashi Iwai <tiwai@suse.de>2012-10-06 16:49:30 +0200
commitd17344b3547669f5b6ee4fda993d03737a141bd6 (patch)
tree2f73c0f42b3b8489d6771f070ec9c801b6e2cc5e
parent395d9dd5dd13c6aa3c8c61a31126af98cd1e747d (diff)
downloadlinux-d17344b3547669f5b6ee4fda993d03737a141bd6.tar.bz2
ALSA: hda - Fix hang caused by race during suspend.
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 <dgreid@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/pci/hda/hda_codec.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 960800b862ab..c0ab72cbeed1 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3612,7 +3612,7 @@ static inline void hda_exec_init_verbs(struct hda_codec *codec) {}
* call suspend and power-down; used both from PM and power-save
* this function returns the power state in the end
*/
-static unsigned int hda_call_codec_suspend(struct hda_codec *codec)
+static unsigned int hda_call_codec_suspend(struct hda_codec *codec, bool in_wq)
{
unsigned int state;
@@ -3620,7 +3620,9 @@ static unsigned int hda_call_codec_suspend(struct hda_codec *codec)
codec->patch_ops.suspend(codec);
hda_cleanup_all_streams(codec);
state = hda_set_power_state(codec, AC_PWRST_D3);
- 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);
@@ -4478,7 +4480,7 @@ static void hda_power_work(struct work_struct *work)
}
spin_unlock(&codec->power_lock);
- state = hda_call_codec_suspend(codec);
+ state = hda_call_codec_suspend(codec, true);
codec->pm_down_notified = 0;
if (!bus->power_keep_link_on && (state & AC_PWRST_CLK_STOP_OK)) {
codec->pm_down_notified = 1;
@@ -5127,7 +5129,7 @@ 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;
}