Nouveau - Jun 2021 - Trouble with TTM patches w/nouveau in linux-next

Hi,

I'm observing nouveau not initializing recently on linux-next on my 
Tegra186 Jetson TX2 board. Specifically it looks like BO allocation is 
failing when initializing the sync subsystem:

[   21.858149] nouveau 17000000.gpu: DRM: failed to initialise sync 
subsystem, -28

I have been bisecting and I have found two patches that affect this. 
Firstly, things first break on

d02117f8efaa drm/ttm: remove special handling for non GEM drivers

starting to return error code -12. Then, at

d79025c7f5e3 drm/ttm: always initialize the full ttm_resource v2

the error code changes to the above -28.

If I checkout one commit prior to d79025c7f5e3 and revert d02117f8efaa, 
things work again. There are a bunch of other TTM commits between this 
and HEAD, so reverting these on top of HEAD doesn't work. However, I 
checked that both yesterday's and today's nexts are also broken.

Thank you,
Mikko

Hi Mikko,

strange sounds like Nouveau was somehow also using the GEM workaround 
for VMWGFX as well.

But -12 means -ENOMEM which doesn't fits into the picture.

I will try with a G710, but if that doesn't yields anything I need some 
more input from you.

Thanks for the report,
Christian.


Am 09.06.21 um 15:47 schrieb Mikko Perttunen:
> Hi,
>
> I'm observing nouveau not initializing recently on linux-next on my 
> Tegra186 Jetson TX2 board. Specifically it looks like BO allocation is 
> failing when initializing the sync subsystem:
>
> [?? 21.858149] nouveau 17000000.gpu: DRM: failed to initialise sync 
> subsystem, -28
>
> I have been bisecting and I have found two patches that affect this. 
> Firstly, things first break on
>
> d02117f8efaa drm/ttm: remove special handling for non GEM drivers
>
> starting to return error code -12. Then, at
>
> d79025c7f5e3 drm/ttm: always initialize the full ttm_resource v2
>
> the error code changes to the above -28.
>
> If I checkout one commit prior to d79025c7f5e3 and revert 
> d02117f8efaa, things work again. There are a bunch of other TTM 
> commits between this and HEAD, so reverting these on top of HEAD 
> doesn't work. However, I checked that both yesterday's and
today's
> nexts are also broken.
>
> Thank you,
> Mikko
>