[PATCH] ALSA: hda/realtek: Serialize setting GPIO LED

[Kai-Heng Feng]

> On Jul 1, 2020, at 14:46, Takashi Iwai <tiwai at suse.de> wrote:
> 
> On Wed, 01 Jul 2020 07:21:35 +0200,
> Kai-Heng Feng wrote:
>> 
>> If a system has two GPIO controlled LED, one for mute and another one
>> for micmute, and both of them are on before system suspend, sometimes
>> one of them won't be turned off by system suspend.
>> 
>> The codec doesn't seem to be able to control multiple GPIO LEDs at the
>> same time, so introduce a new mutex to serialize setting the LED, to
>> prevent the issue from happening.
>> 
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
>> ---
>> include/sound/hda_codec.h     | 1 +
>> sound/pci/hda/hda_codec.c     | 1 +
>> sound/pci/hda/patch_realtek.c | 3 +++
>> 3 files changed, 5 insertions(+)
>> 
>> diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h
>> index d16a4229209b..3a1792bbb7ac 100644
>> --- a/include/sound/hda_codec.h
>> +++ b/include/sound/hda_codec.h
>> @@ -206,6 +206,7 @@ struct hda_codec {
>> 
>> 	struct mutex spdif_mutex;
>> 	struct mutex control_mutex;
>> +	struct mutex led_mutex;
> 
> Since it's only for Realtek codec, can it be better in alc_spec
> instead?

Ok, I found that the mutex just papers over the real issue.

The root cause is that led_set_brightness_nopm() use schedule_work() but the work queue doesn't gets flushed.
I'll fix it there properly.

Kai-Heng

> 
> 
> thanks,
> 
> Takashi