Re: [PATCH v3 1/2] ALSA: hda/realtek: Add COEF controlled micmute LED support

[Kai-Heng Feng <kai.heng.feng@canonical.com>]

> On Jun 17, 2020, at 23:50, Takashi Iwai <tiwai@suse.de> wrote:
> 
> On Wed, 17 Jun 2020 17:24:30 +0200,
> Kai-Heng Feng wrote:
>> 
>> 
>> 
>>> On Jun 17, 2020, at 19:55, Takashi Iwai <tiwai@suse.de> wrote:
>>> 
>>> On Wed, 17 Jun 2020 12:29:01 +0200,
>>> Kai-Heng Feng wrote:
>>>> 
>>>> Currently, HDA codec LED class can only be used by GPIO controlled LED.
>>>> However, there are some new systems that control LED via COEF instead of
>>>> GPIO.
>>>> 
>>>> In order to support those systems, create a new helper that can be
>>>> facilitated by both COEF controlled and GPIO controlled LED.
>>>> 
>>>> In addition to that, add LED_CORE_SUSPENDRESUME flag since some systems
>>>> don't restore the LED properly after suspend.
>>>> 
>>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>> 
>>> Thanks for the quick follow up, the issues I pointed were fixed.
>>> 
>>> But, now looking at the code change again, I'm no longer sure whether
>>> it's the right move.
>>> 
>>> Basically, the led cdev should serve only for turning on/off the LED
>>> as given.  But your patch changes it to call the generic mixer
>>> updater, which is rather the one who would call the led cdev state
>>> update itself.  That is, it's other way round.
>>> 
>>> IMO, what we need is to make all places calling
>>> snd_hda_gen_add_micmute_led() to create led cdev, and change those
>>> calls with snd_hda_gen_fixup_micmute_led().
>> 
>> Ok, so it's the same as patch v1.
>> How should we handle vendors other than HP?
>> Only create led cdev if the ID matches to HP?
> 
> It's fine to create a LED classdev for other vendors, too.  But the
> problem is that it wasn't consistent.  With the LED classdev, we
> should use only cdev, instead of mixing up different ways.

Ok, now I get what you meant...

> 
> I wrote a few patches to convert those mic-mute LED stuff to classdev,
> including some cleanups.  The patches are found in
> topic/hda-micmute-led branch of sound git tree.  Could you check it?
> 
> Note that it's totally untested.  Also it doesn't contain yet
> LED_CORE_SUSPENDRESUME, which should be done in another patch in
> anyway.

Other than LED_CORE_SUSPENDRESUME, it works great!

Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

> 
>>> It'll be a bit more changes and likely not fitting with 5.8, but the
>>> whole result will be more consistent.
>> 
>> A bit off topic, but do you think it's reasonable to also create led cdev for mute LED, in addition to micmute LED?
>> I just found that the LEDs are still on during system suspend, and led cdev has the ability to turn off the LEDs on system suspend.
> 
> Yes, it makes sense, too.  But the playback mute handling is a bit
> more complicated than the mic-mute LED because it's implemented with a
> vmaster hook.  I'll take a look later.

Thanks. I'll be happy to test it.

Kai-Heng

> 
> 
> thanks,
> 
> Takashi