[Nouveau] nouveau TRAP_M2MF still there on G98

[Māris Nartišs]

2018-04-05 2:03 GMT+03:00, Ilia Mirkin <imirkin at alum.mit.edu>:
> On Wed, Apr 4, 2018 at 6:58 PM, Adam Borowski <kilobyte at angband.pl> wrote:
>> On Wed, Apr 04, 2018 at 03:48:39PM +0300, Māris Nartišs wrote:
>>> Still your report makes to question the original commit I was fixing
>>> (mmu: swap out round for ALIGN). Could you test if going back to
>>> rounddown fixes problem on your side?
>>>
>>> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
>>> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
>>> @@ -1354,7 +1354,7 @@ nvkm_vmm_get_locked(struct nvkm_vmm *vmm, bool
>>> getref, bool mapref, bool sparse,
>>>
>>>                 tail = this->addr + this->size;
>>>                 if (vmm->func->page_block && next && next->page != p)
>>> -                       tail = ALIGN_DOWN(tail, vmm->func->page_block);
>>> +                       tail = rounddown(tail, vmm->func->page_block);
>>>
>>>                 if (addr <= tail && tail - addr >= size) {
>>>                         rb_erase(&this->tree, &vmm->free);
>>>
>>
>> Alas, it did work for a few hours, then a total display freeze:
>>
>> [29982.011795] nouveau 0000:01:00.0: fifo: DMA_PUSHER - ch 2 [Xorg[2667]]
>> get
>> 0000037d90 put 000003a2cc ib_get 000001dc ib_put 000001dd state 80004861
>> (err:
>> INVALID_CMD) push 00704031
>> [29982.027959] nouveau 0000:01:00.0: fifo: DMA_PUSHER - ch 2 [Xorg[2667]]
>> get
>> 000003a2cc put 000003a2cc ib_get 000001dc ib_put 000001f9 state 80000000
>> (err:
>> INVALID_CMD) push 00406040
>
> These, as I call them, 406040 errors, have been around on Tesla for
> ages. We have no idea what leads to them, but generally some kind of
> fifo desync appears to follow.
>
>   -ilia

Taking this into account, going back to rounddonw from ALIGN_DOWN
seems to fix breakage on some systems. Lets wait for Ben's input on
this matter, as he swapped rounddown with ALIGN_DOWN to fix some kind
of build problems on 32bit systems.

Ilia, is there anything we could add to our kernels to shed some light
on 406040 errors? I am not certain if I have seen those on my
hardware, but, as you say, they might be rare enough to not remember
it.

Māris.