Comment 158 for bug 1803179

(In reply to Matthias Fulz from comment #141)
> (In reply to arpie from comment #140)
[snip]
> > If I completely disable the audio card using :
> > echo 1 | sudo tee /sys/bus/pci/devices/0000:01:00.1/remove
> >
> > Then the system hangs are completely cured
>
> Not working for me. Still freezing with this.

Any chance of more details? When and how is it freezing? Is it any different from before? What are your machine/card details (looks like you haven't posted these anywhere above)?

Also, are you absolutely sure you've disabled the audio card during boot *before the kernel notices it is there*? The only reliable way I've found to check if this is the case, is to run powertop, and look in the 'Device Status' tab for listings of 'Audio codec hwXXXXX: nvidia'. If that is showing up, then the nvidia sound card is still active and will cause hangs. My solution only works if the audio card is removed/disabled before the audio system initialises during boot (hence the WantedBy=sysinit.target in my service file).

I think I should have also mentioned that in order for the kernel to do the PM, you need to do something like :

echo auto | sudo tee /sys/bus/pci/devices/0000:01:00.0/power/control

I have TLP installed, which does this for me.

Now a few days have passed, I admit I have had a few freezes when using bbswitch. But if I disable bbswitch and just use bumblebee with no power management, all is well (so far). If I want to power down the nvidia GFX card I just manually modprobe -r nvidia and the kernel does the rest. Using this solution, I see a drop from about 20W to 10W when the card powers off, with no ACPI calls at all (or, rather, none that I am aware of - I have no idea what the kernel is actually doing behind the scenes).

I am sure that there must be a 'proper' solution where the correct ACPI commands are used to power off/on both the nvidia video and audio at the same time but finding such a solution is far beyond me...