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* [REGRESSION] Audio popping on ThinkPad X1 Carbon Gen 12 (ALC287) after commit d2e01e0c5e94
@ 2026-03-10  0:01 Jérémy Bethmont
  2026-03-10  6:47 ` Takashi Iwai
  0 siblings, 1 reply; 5+ messages in thread
From: Jérémy Bethmont @ 2026-03-10  0:01 UTC (permalink / raw)
  To: Takashi Iwai; +Cc: Kailang Yang, alsa-devel, regressions, regressions

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?

Thank you for your time and work on this.

Best regards,
Jeremy

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2026-03-12 15:24 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-03-10  0:01 [REGRESSION] Audio popping on ThinkPad X1 Carbon Gen 12 (ALC287) after commit d2e01e0c5e94 Jérémy Bethmont
2026-03-10  6:47 ` Takashi Iwai
2026-03-10  8:24   ` Jérémy Bethmont
2026-03-10  8:32     ` Takashi Iwai
2026-03-10  9:40       ` Jérémy Bethmont

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