Re: [PATCH] ALSA: hda/realtek: Limit internal mic boost on HP Pavilion 15 (103c:2164)

[Takashi Iwai <tiwai@suse.de>]

On Mon, 21 Sep 2026 22:55:38 +0200,
Hernan Ganzo wrote:
> 
> The HP Pavilion 15 with the ALC3227 codec (SSID 103c:2164) exposes the full
> four-step internal mic boost on pin 0x12: nsteps=3 with stepsize=0x2f, that is
> 0, 12, 24 and 36 dB. Combined with the ADC capture gain of +30 dB the analogue
> cascade reaches 66 dB, and the internal microphone clips on the ambient noise of
> a quiet room; the upper two steps are unusable at any useful input level. This
> is the defect class ALC269_FIXUP_LIMIT_INT_MIC_BOOST exists for.
> 
> The machine matches no SSID quirk and falls through to the pin table, which
> selects ALC269_FIXUP_HP_MUTE_LED_MIC1 through a pin signature shared with
> several other HP models. Add an SSID entry instead, using
> ALC269_FIXUP_LIMIT_INT_MIC_BOOST_MUTE_LED: the existing fixup that applies
> alc269_fixup_limit_int_mic_boost() and chains to the same mute LED fixup, as
> already done for 103c:218b. The boost becomes 0 or 12 dB and the LED handling is
> unchanged.
> 
> Tested on the affected machine by selecting the same fixup through the model
> string (snd-hda-intel.model), which bypasses the SSID and pin tables, with the
> driver confirming the selection:
> 
>   snd_hda_codec_alc269 hdaudioC1D0: ALC3227: picked fixup limit-mic-boost (model specified)
> 
> With that, Internal Mic Boost reports Limits 0 - 1 (0 or 12 dB) instead of 0 - 3
> (0 to 36 dB), so alc269_fixup_limit_int_mic_boost() clamps this codec's internal
> mic pin as intended. Note that /proc/asound/card1/codec#0 keeps printing the
> unclamped hardware caps (nsteps=0x03): that file reads codec parameters uncached
> by design, while the fixup overrides the driver's cached parameter that the
> control is built from.
> 
> This does not by itself make the default capture volume sane -- the remaining
> 12 dB on top of the +30 dB ADC gain is still hotter than this machine's usable
> operating point. It removes the two unusable steps from the hardware range, which
> is what a quirk of this class can do.
> 
> Signed-off-by: Hernan Ganzo <gp@sneemgp.com>

Applied now.  Thanks.


Takashi