Commit d17344b3 authored by Dylan Reid's avatar Dylan Reid Committed by Takashi Iwai

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: default avatarDylan Reid <dgreid@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 395d9dd5
...@@ -3612,7 +3612,7 @@ static inline void hda_exec_init_verbs(struct hda_codec *codec) {} ...@@ -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 * call suspend and power-down; used both from PM and power-save
* this function returns the power state in the end * 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; unsigned int state;
...@@ -3620,7 +3620,9 @@ static unsigned int hda_call_codec_suspend(struct hda_codec *codec) ...@@ -3620,7 +3620,9 @@ static unsigned int hda_call_codec_suspend(struct hda_codec *codec)
codec->patch_ops.suspend(codec); codec->patch_ops.suspend(codec);
hda_cleanup_all_streams(codec); hda_cleanup_all_streams(codec);
state = hda_set_power_state(codec, AC_PWRST_D3); 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); spin_lock(&codec->power_lock);
snd_hda_update_power_acct(codec); snd_hda_update_power_acct(codec);
trace_hda_power_down(codec); trace_hda_power_down(codec);
...@@ -4478,7 +4480,7 @@ static void hda_power_work(struct work_struct *work) ...@@ -4478,7 +4480,7 @@ static void hda_power_work(struct work_struct *work)
} }
spin_unlock(&codec->power_lock); spin_unlock(&codec->power_lock);
state = hda_call_codec_suspend(codec); state = hda_call_codec_suspend(codec, true);
codec->pm_down_notified = 0; codec->pm_down_notified = 0;
if (!bus->power_keep_link_on && (state & AC_PWRST_CLK_STOP_OK)) { if (!bus->power_keep_link_on && (state & AC_PWRST_CLK_STOP_OK)) {
codec->pm_down_notified = 1; codec->pm_down_notified = 1;
...@@ -5127,7 +5129,7 @@ int snd_hda_suspend(struct hda_bus *bus) ...@@ -5127,7 +5129,7 @@ int snd_hda_suspend(struct hda_bus *bus)
list_for_each_entry(codec, &bus->codec_list, list) { list_for_each_entry(codec, &bus->codec_list, list) {
if (hda_codec_is_power_on(codec)) if (hda_codec_is_power_on(codec))
hda_call_codec_suspend(codec); hda_call_codec_suspend(codec, false);
} }
return 0; return 0;
} }
......
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