[PATCH 1/1] ALSA: hda/realtek: fix mic boost on Intel NUC 8

[Takashi Iwai]

On Fri, 16 Apr 2021 00:01:29 +0200,
Phil Calvin wrote:
> 
> Fix two bugs with the Intel HDA Realtek ALC233 sound codec
> present in Intel NUC NUC8i7BEH and probably a few other similar
> NUC models.
> 
> These codecs advertise a 4-level microphone input boost amplifier on
> pin 0x19, but the highest two boost settings do not work correctly,
> and produce only low analog noise that does not seem to contain any
> discernible signal. There is an existing fixup for this exact problem
> but for a different PCI subsystem ID, so we re-use that logic.
> 
> Changing the boost level also triggers a DC spike in the input signal
> that bleeds off over about a second and overwhelms any input during
> that time. Thankfully, the existing fixup has the side effect of
> making the boost control show up in userspace as a mute/unmute switch,
> and this keeps (e.g.) PulseAudio from fiddling with it during normal
> input volume adjustments.
> 
> Finally, the NUC hardware has built-in inverted stereo mics. This
> patch also enables the usual fixup for this so the two channels cancel
> noise instead of the actual signal.
> 
> Signed-off-by: Phil Calvin <phil at philcalvin.com>

Thanks, applied now with a minor fix of the quirk entry position
(sorted in order).

But the patch text wasn't cleanly applicable and I had to edit it
manually.  I guess this is due to your MUA setup.  Please check it and
fix at the next time.


Takashi