Yeah, exactly that's the root cause of the problem.
GEM objects are the base class for TTM BOs for quite a while now.
So we at least need to initialize them or otherwise at least the size of the object is not available.
Going to send a fix in a few minutes.
Thanks, Christian.
Am 09.06.21 um 17:13 schrieb Ilia Mirkin:
GEM init happens here:
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcgit.freed...
Note the bo alloc / gem init / bo init dance.
I don't think there is a GEM object for internal allocations at all -- we just allocate bo's directly and that's it. Perhaps you meant something else? I thought GEM was meant for externally-available objects.
Cheers,
-ilia
On Wed, Jun 9, 2021 at 10:58 AM Christian König christian.koenig@amd.com wrote:
Good point, but I think that is unrelated.
My suspicion is rather that nouveau is not initializing the underlying GEM object for internal allocations.
So what happens is the same as on VMWGFX that TTM doesn't know anything about the size to of the BO resulting in a kmalloc() with a random value and eventually -ENOMEM.
Good news is that I can reproduce it, so going to look into that later today.
Regards, Christian.
Am 09.06.21 um 16:52 schrieb Ilia Mirkin:
Christian - potentially relevant is that Tegra doesn't have VRAM at all -- all GTT (or GART or whatever it's called nowadays). No fake/stolen VRAM.
Cheers,
-iliaOn Wed, Jun 9, 2021 at 10:18 AM Christian König christian.koenig@amd.com wrote:
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
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