Re: [REGRESSION] Audio popping on ThinkPad X1 Carbon Gen 12 (ALC287) after commit d2e01e0c5e94

[Takashi Iwai <tiwai@suse.de>]

On Tue, 10 Mar 2026 01:01:11 +0100,
Jérémy Bethmont wrote:
> 
> Hi Takashi, Kailang,
> 
> I am reporting an audio regression introduced in kernel 6.18.13 on the
> Lenovo ThinkPad X1 Carbon Gen 12 (Meteor Lake, Realtek ALC287 codec,
> SSID: 0x17aa231e).
> 
> Since this update, the laptop emits a short, noticeable hardware
> pop/blip from the speakers exactly when an audio stream closes and the
> PCM state suspends. It happens consistently a few seconds after
> playback finishes (e.g., after a system notification or terminal
> bell).
> 
> I have tracked the regression down to the following commit:
> d2e01e0c5e947da0b5005ca89efa82baeb232adc ("ALSA: hda/realtek - fixed
> speaker no sound")
> 
> #regzbot introduced: d2e01e0c5e947da0b5005ca89efa82baeb232adc
> 
> Root cause analysis:
> The commit modifies the `alc287_alc1318_playback_pcm_hook` function,
> adding raw COEF writes to disable/enable AMP silence detection on
> HDA_GEN_PCM_ACT_OPEN and HDA_GEN_PCM_ACT_CLOSE.
> 
> Because `alc287_alc1318_playback_pcm_hook` is a shared hook used by
> multiple Lenovo ALC287/ALC1318 devices, these unconditional
> `WRITE_COEF` instructions are being sent to hardware that does not
> need the silence detection fix. On the X1 Carbon Gen 12, executing
> `alc_process_coef_fw(codec, en_coefs)` upon stream close triggers an
> immediate electrical pop. Monitoring with `pw-mon` confirms the
> hardware pop coincides perfectly with the monitor_FR / monitor_FL
> ports going idle/suspended.
> 
> Proposed solution:
> Could we revert this commit, or alternatively, wrap these specific
> silence-detection COEF writes in a targeted `ALC287_FIXUP` quirk
> matched via SSID/DMI, rather than executing them globally in the
> shared playback hook?

Could you give alsa-info.sh output?  Run the script with --no-upload
option and attach the output.

I guess the bug might not be specific to your device but happening in
general with all matching ones.  As a workaround for such a pop noise,
we often need to reorder verbs or put some delay between verbs.


Takashi