Low level interfering crackling/popping of the speakers while playing no sound

[mkopec]

Issue migrated from GitLab

Dasharo version

v0.5.0

Hardware details

Clevo NV40MZ-i7

Affected component(s) or functionality

Speakers

Brief summary

While not playing any sound, the speakers are lightly cracking, like an interfering sound.

How reproducible

100% reproducible.

How to reproduce

Steps to reproduce the behavior:

1. Turn on the laptop.
2. Boot into Windows or Ubuntu.
3. Notice the speakers that are very lightly cracking or popping.

Expected behavior

No speakers crackling.

Actual behavior

Speakers crackling.

Screenshots

Additional context

This issue does not happen on original Insyde firmware. Perhaps the speakers are muted if no sound is detected?

Solutions you've tried

None.

/cc @macpijan

[mkopec]

Note: This is likely to be coil whine that appears while the device is idle (especially noticeable in deeper C-states)

[macpijan]

Report from NovaCustom is that the Insyde firmware has the same behavior.

[mkopec]

Happens every time the device reaches C-state C8 or lower, including when it's idling with the screen off (or in self-refresh if applicable) and in S0ix sleep.

[Brice123456789]

NovaCustom NV40 computer, Intel Core i5. Firmware 1.4. Debian 12 GNOME.

This behavior happens with power-profiles-daemon in "Performance mode".
The use of TLP instead of power-profiles-daemon triggers this too.

[wessel-novacustom]

@mkopec is there any possible firmware solution for this, you think?

[mkopec]

@wessel-novacustom coil whine can be mitigated using Acoustic Noise Optimization. We did some testing a while ago to see if it could help, but the various settings for this feature need some testing for stability (since they affect SoC power delivery) so as of now it's not enabled.

[wessel-novacustom]

That's great. How exactly can we enable this? Can that be done by firmware?

[mkopec]

Can that be done by firmware?

@wessel-novacustom Yes, it's a set of options in Intel FSP

[wessel-novacustom]

Ok, perfect. It would be great if it could be implemented for a next firmware update or even the October update.

[wessel-novacustom]

Dasharo/coreboot#428 (comment)

[mkopec]

Acoustic Noise Mitigation was implemented for ADL models in commit Dasharo/coreboot@cad41c1 and TGL in commits Dasharo/coreboot@30d9759 and Dasharo/coreboot@ca9a0b3

This not only reduced coil whine, but also fixed some freezes and glitches in the board logic. Before these changes I saw the ACIN signal on EC turning on randomly despite there being no charger plugged in

[wessel-novacustom]

The noise has been reduced massively with the latest test binaries indeed, so I believe this should be marked as solved @mkopec.

[mkopec]

RFI mitigation on TGL might also help with Bluetooth and WiFi reception :) Not sure about ADL though