I recently updated from the 4.9 kernel to 4.14 only to find my speakers have a constant buzzing sound. I've narrowed the problem down to the
power_save parameter of the
snd_hda_intel module. When enabled there is a constant buzz, but disabled (set to 0) it is silent.
I've attempted to set the value by using both a
modprobe.d and a kernel parameter. The problem is, the value is being overwritten/set by something in my system.
Forcefully reloading the module (default is off) or writing 0 to
/sys/module/snd_hda_intel/parameters/power_save will temporarily solve the problem, until a reboot or wake from suspend. I cannot determine what is enabling the power_save feature. I've even tried using
lsof to find the culprit, with no results (doesn't seem to work across sleep/wake cycles).
This is a desktop PC, so no battery hence no AC vs BAT modes or anything like pm-util. I'm using a GNOME version of Manjaro, but I'm sure solutions for any platform may help. The audio is an onboard ALC887-VD chipset if that's any help.
Can anybody suggest where else I might look or what could be causing this?
I've noticed my distribution shipped with TLP (similar to
pm-utils) and that on the 4.14 kernel TLP always starts up in battery mode. My PC doesn't have a battery but does have wireless peripherals. I think this may be a bug within TLP itself.