[Nouveau] nouveau kms causing hibernation problems

[Marcin Kościelnicki]

> I have an old machine with working hibernation (pm-hibernate). I replaced
> the graphics card with an NV05 one and now it fails to hibernate when using
> modesetting. nouveau.modeset=0 works fine.
>
> What happens is that very early in the process the display looses signal,
> and the expected disk activity never happens (no led flashing). Then the
> machine just hangs. I suspect that the progress information shown on the
> VGA console in modeset=0 has issues with the framebuffer, and it crashes
> there.
>
> On the other hand, googling for this gives me nothing, so I guess others
> have this working fine.

There are not that many users of NV04/NV05....

> Any ideas how to debug this?

This may be a result of a known bug in our BIOS script interpreter. Go to your 
kernel tree, drivers/gpu/drm/nouveau/nouveau_bios.c, go to init_compute_mem 
function, and try commenting out the "bios_wr32(bios, NV_PFB_REFCTRL, 
NV_PFB_REFCTRL_VALID_1);" line.

This bug is sure to break suspend on all NV4 and NV5, it probably affects 
hibernate too.

Please report if removing this line changes things for you.

Marcin Kościelnicki