On Tue, Aug 30, 2016 at 11:25 AM, Roland Singer <roland.sin...@desertbit.com> wrote: > I tried these scenarios: > > 1. Booted the system without the bbswitch module. The nouveau module > was loaded and is responsible for the power management of the GPU. > The graphical session freezes after some minutes... > > 2. Booted the system without bbswitch and with nouveau blacklisted. > Manually loaded bbswitch to switch off the discrete GPU. > Same freeze after a while or by explicitly obtaining the GPU state. > > Is there a possibility to switch off the discrete card without bbswitch? > If this is possible, then I could test this without nouveau and bbswitch > at all. If the system hangs, then it is not the video driver nor bbswitch.
You can use acpi_call (a random search points to https://github.com/mkottman/acpi_call, but I don't know if that's the "official" version) - need to find the right method to call, but that's basically all it takes to acpi-suspend a gpu. Separately, there was a recent fix to ... something, including but not limited to nouveau, involving hangs on gpu suspend on newer laptops. I don't think it's upstream yet. Look for patches from Lukas Wunner. -ilia
