On Mon, 26 Nov 2018 00:17:15 +0100, Alexander Kappner wrote:
My Lenovo P50 laptop has a BIOS option to disable the microphone. When this option gets chosen, the snd_hda_intel driver causes high CPU load on a single kworker thread, spinning on "process_unsol_events", and system instability. This behavior occurs from the time that the snd_hda_intel module is loaded, irrespective of whether anything is attempting to access the mic. The sound output still works.
When in this state, the module cannot be removed cleanly; attempting to remove it (even without rmmod -f) triggers an oops.
I have attached two exemplary dmesg outputs. Strangely enough, the exact location of the oops varies, but further up the call chain, I always see process_unsol_events.
When the mic is not disabled in the BIOS, the module works stable, regardless whether or not the mic is muted in ALSA.
I wasn't able to pinpoint the root cause. Any pointers on where to start? Much appreciated.
Could you load snd-hda-intel driver with probe_only=1 option, and give alsa-info.sh output (run it with --no-upload option)? This should leave only the codec probing without configuring, so we can see the codec widget contents and check the emulator.
thanks,
Takashi