Re: [PATCH v4 2/2] ASoC: rt715:add micmute led state control supports

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 3/22/21 3:37 PM, Jaroslav Kysela wrote:
> Dne 22. 03. 21 v 10:25 Yuan, Perry napsal(a):
>> Hi Mark:
>>
>>> -----Original Message-----
>>> From: Mark Brown <broonie@kernel.org>
>>> Sent: Tuesday, March 9, 2021 1:24 AM
>>> To: Yuan, Perry
>>> Cc: pobrn@protonmail.com; pierre-louis.bossart@linux.intel.com;
>>> oder_chiou@realtek.com; perex@perex.cz; tiwai@suse.com;
>>> hdegoede@redhat.com; mgross@linux.intel.com; Limonciello, Mario;
>>> lgirdwood@gmail.com; alsa-devel@alsa-project.org; linux-
>>> kernel@vger.kernel.org; platform-driver-x86@vger.kernel.org
>>> Subject: Re: [PATCH v4 2/2] ASoC: rt715:add micmute led state control
>>> supports
>>>
>>> On Mon, Mar 01, 2021 at 05:38:34PM +0800, Perry Yuan wrote:
>>>
>>>> +	/* Micmute LED state changed by muted/unmute switch */
>>>> +	if (mc->invert) {
>>>> +		if (ucontrol->value.integer.value[0] || ucontrol-
>>>> value.integer.value[1]) {
>>>> +			micmute_led = LED_OFF;
>>>> +		} else {
>>>> +			micmute_led = LED_ON;
>>>> +		}
>>>> +		ledtrig_audio_set(LED_AUDIO_MICMUTE, micmute_led);
>>>> +	}
>>>
>>> These conditionals on inversion seem weird and counterintuitive.  If we're
>>> going with this approach it would probably be clearer to define a custom
>>> operation for the affected controls that wraps the standard one and adds the
>>> LED setting rather than keying off invert like this.
>>
>> Currently the sof soundwire driver has no generic led control yet.
>> This patch can handle the led control needs for MIC mute LED, definitely the patch is a short term solution.
>> There is a feature request discussion when we started to implement this solution.
>> https://github.com/thesofproject/linux/issues/2496#issuecomment-713892620
>>
>> The workable way for now is that we put the LED mute control to the codec driver.
>> When there is new and full sound LED solution implemented, this part will be also optimized.
>> The Hardware privacy feature needs this patch to handle the Mic mute led state change.
>> Before that full solution ready in kernel, could we take this as short term solution?
> 
> Perry, it's about the machine detection. Your code is too much generic even
> for the top-level LED trigger implementation. We need an extra check, if the
> proper LED's are really controlled on the specific hardware. Other hardware
> may use RT715 for a different purpose. Use DMI / ACPI checks to detect this
> hardware and don't misuse the inversion flag to enable this code.

I think this would be a goo candidate for the new generic LED handling:

https://lore.kernel.org/alsa-devel/20210317172945.842280-1-perex@perex.cz/

And then use a udev-rule + hwdb and/or UCM profiles to configure the LED trigger
for specific models from userspace ?

Regards,

Hans