linux-kernel - Re: [PATCH] ALSA: hda: Skip creating captures in SOF context

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Date:   Tue, 19 Jul 2022 17:41:46 +0200
From:   Jaroslav Kysela <perex@...ex.cz>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>, tiwai@...e.com
Cc:     Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ALSA: hda: Skip creating captures in SOF context

Dne 19. 07. 22 v 16:47 Kai-Heng Feng napsal(a):
> On HP laptops that use SOF driver for DMIC, the micmute LED doesn't
> light up when mic is muted after commit 9b014266ef8a ("ASoC: SOF:
> topology: use new sound control LED layer").
> 
> The micmute LED itself is still working via sysfs, but it doesn't follow
> mute anymore. That's because unlike vendors like Dell and Lenovo, HP
> laptops use HDA codec to control mute LEDs instead of ACPI. So on HP
> laptops, both SOF and HDA create captures with
> SNDRV_CTL_ELEM_ACCESS_MIC_LED access, snd_ctl_led_set_state() considers
> there are two different kcontrols and one of them is not muted.

It does not mean that it's a wrong behavior. When both controls are muted, the
LED should be turned on. It just requires that all inputs are off (and it may
be the default - probably we can set in UCM or so). If you turn the "Capture
Switch" off in amixer / alsamixer, do things work as expected ?

> So skip creating captures for HDA when it's called from SOF, the
> captures are already handled by SOF.

The capture controls are for other inputs like external analog microphone. If
it is required to suppress the MIC LED for some hardware, just skip the
"spec->mic_mute_led = 1" assignment in hda_generic.c . Also, the check
"codec->core.type != HDA_DEV_ASOC" is not sufficient, because you don't know,
if the topology really sets the MIC LED flag.

					Jaroslav

-- 
Jaroslav Kysela <perex@...ex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.