nvidia.conf: Enable S0ix Power Management

[ptr1337]

This has been enabled by Suse and Fedora since a while. Lets also enable this for newer GPUs, which should yield longer battery time, when in sleep.

[ventureoo]

reducing battery drain—especially on laptops

Is there any source? Because the NVIDIA documentation is not so clear about this:

S0ix-based suspend will consume more power than legacy S3 system suspend, but it will enter and exit suspend/resume more quickly.

(https://download.nvidia.com/XFree86/Linux-x86_64/580.65.06/README/powermanagement.html)

Generally, I don't mind, just want to make sure there are no major regressions.

[Fabback]

@ptr1337
I've had no problem for a few month with suspend on my NVidia GTX 970, but since a few days it crashes again and displays a long journal full screen with no way out. After removing this parameter, then restarting, suspend seems to work again (i've only tried once after a 2 min inactivity)
Will this parameter revert back automatically on any update ?

Edit :
I've ran this command with a "Not Supported" result
grep 'Video Memory Self Refresh' /proc/driver/nvidia/gpus/0000\:01\:00.0/power