Re: [PATCH 3/4] ASoC: amd: acp: Add machine driver that enables sound for systems with a ES8336 codec

[Marian Postevca <posteuca@mutex.one>]

Mark Brown <broonie@kernel.org> writes:

> On Wed, Mar 22, 2023 at 12:17:24AM +0200, Marian Postevca wrote:
>> Mark Brown <broonie@kernel.org> writes:
>
>> >> +	if (SND_SOC_DAPM_EVENT_ON(event))
>> >> +		acp3x_es83xx_set_gpios_values(priv, 1, 0);
>> >> +	else
>> >> +		acp3x_es83xx_set_gpios_values(priv, 0, 1);
>
>> > Why are these two GPIOs tied together like this?
>
>> These GPIOs represent the speaker and the headphone switches. When
>> activating the speaker GPIO you have to deactivate the headphone GPIO
>> and vice versa. The logic is taken from the discussion on the sofproject
>> pull request:
>> https://github.com/thesofproject/linux/pull/4112/commits/810d03e0aecdf0caf580a5179ee6873fb33485ab
>> and
>> https://github.com/thesofproject/linux/pull/4066
>
> Sure, but that doesn't answer the question.  What is the reason
> they're tied together - what if someone wants to play back from
> both speaker and headphones simultaneously?
>

The GPIO handling is not documented in the codec datasheet, so I
constructed this logic by looking at the existing implementations of
machine drivers for this codec (sof_es8336.c, bytcht_es8316.c) and
comments of Everest Semiconductor engineers on the sofproject
pull requests. I'm saying all of this because I don't know the reasons
why these GPIOs work the way they do.

According to the Everest Semiconductor engineers this is the recommended
way to switch these GPIOs:

+--------------+--------------+----------------+
|              | Speaker GPIO | Headphone GPIO |
+--------------+--------------+----------------+
| Speaker on   | active       | inactive       |
| Headphone on | inactive     | active         |
| Suspended    | inactive     | inactive       |
+--------------+--------------+----------------+
(https://github.com/thesofproject/linux/pull/4066/commits/b7f12e46a36b74a9992920154a65cd55f5b0cdb4#r1041693056)

This lockstep between these two GPIOs can be seen in sof_es8336.c in
pcm_pop_work_events() too.

Regarding playing the speaker and headphone simultaneously, is not
something I took into account. Is this even a valid usecase? The intel driver
for es8336 doesn't seem to support it.

Maybe someone from Everest Semiconductor can comment on this GPIO handling?

>> >> +static int acp3x_es83xx_suspend_pre(struct snd_soc_card *card)
>> >> +{
>> >> +	struct acp3x_es83xx_private *priv = get_mach_priv(card);
>> >> +
>> >> +	dev_dbg(priv->codec_dev, "card suspend\n");
>> >> +	snd_soc_component_set_jack(priv->codec, NULL, NULL);
>> >> +	return 0;
>> >> +}
>
>> > That's weird, why do that?
>
>> This is needed because if suspending the laptop with the headphones
>> inserted, when resuming, the sound is not working anymore. Sound stops
>> working on speakers and headphones. Reinsertion and removals of the
>> headphone doesn't solve the problem.
>
>> This seems to be caused by the fact
>> that the GPIO IRQ stops working in es8316_irq() after resume.
>
> That's a bug that should be fixed.

Agreed, but I don't know how easy it is to fix, and I would like to
first offer users of these laptops a working sound driver.
Afterwards this issue can be analyzed and properly fixed.