On 2020-06-16 10:13:27 [+0200], Stephen Berman wrote: > Yes, thanks, that did it. Trace attached. So TZ10 is a temperature sensor of some kind on your motherboard. In your v5.6 dmesg there is: | thermal LNXTHERM:00: registered as thermal_zone0 | ACPI: Thermal Zone [TZ10] (17 C) So. In /sys/class/thermal/thermal_zone0/device/path you should also see TZ10. And /sys/class/thermal/thermal_zone0/temp should show the actual value. This comes from the "thermal" module. Looking at the trace, might query the temperature every second which somehow results in "Dispatching Notify on". I don't understand how it gets from reading of the temperature to the notify part, maybe it is part of the ACPI… However. Could you please make sure that the thermal module is not loaded at system startup? Adding thermal.off=1 to the kernel commandline should do the trick. And you should see thermal control disabled in dmesg. That means your thermal_zone0 with TZ10 does not show up in /sys and nothing should schedule the work-items. This in turn should allow you to shutdown your system without the delay. If this works, could you please try to load the module with tzp=300? If you add this thermal.tzp=300 to the kernel commandline then it should do the trick. You can verify it by cat /sys/module/thermal/parameters/tzp This should change the polling interval from what ACPI says to 30secs. This should ensure that you don't have so many worker waiting. So you should also be able to shutdown the system. > Steve Berman Sebastian