[Nouveau] Meaning of the engines in paramaters of nouveau module

[Dave Airlie]

On Mon, 4 Dec 2023 at 05:04, Paul Dufresne <dufresnep at zoho.com> wrote:
>
> In https://nouveau.freedesktop.org/KernelModuleParameters.html, there is:
> Here is a list of engines:
>     DEVICE
>     DMAOBJ
>     PBSP
>     PCE0
>     PCE1
>     PCE2
>     PCRYPT
>     PDISP
>     PFIFO
>     PGRAPH
>     PMPEG
>     PPM
>     PPPP
>     PVP
>     SW
> Also, in debug:
>    CLIENT
>
> I have tried to find a description of those.
> https://envytools.readthedocs.io/en/latest/
> help a bit, but I don't find a precise correlation.
>
> https://nouveau.freedesktop.org/NouveauTerms.html
> does not seems to have most of these terms.
>
> I am particularly curious about PCE[0-3].
> But also about CLIENT, that seems different and mysterious.
>
> I wonder if it is possible to write:
> nouveau.debug=info,PDISP=debug
> to have the info debug level as the default, but for PDISP have the debug level
>
> Also, my interest is linked to the state of GPU graph given after a context switch timeout that looks like:
> [ 1696.780305] nouveau 0000:01:00.0: fifo: SCHED_ERROR 0a [CTXSW_TIMEOUT]
> [ 1696.780361] nouveau 0000:01:00.0: fifo:000000:00[      gr]: 8006e005: busy 1 faulted 0 chsw 1 save 1 load 1 chid 5*-> chid 6
> [ 1696.780422] nouveau 0000:01:00.0: fifo:000000:07[     ce2]: 00050005: busy 0 faulted 0 chsw 0 save 0 load 0 chid 5 -> chid 5
> [ 1696.780476] nouveau 0000:01:00.0: fifo:000004:04[     ce0]: 00000000: busy 0 faulted 0 chsw 0 save 0 load 0 chid 0 -> chid 0
> [ 1696.780529] nouveau 0000:01:00.0: fifo:000001:01[  mspdec]: 00000000: busy 0 faulted 0 chsw 0 save 0 load 0 chid 0 -> chid 0
> [ 1696.780581] nouveau 0000:01:00.0: fifo:000002:02[   msppp]: 00000000: busy 0 faulted 0 chsw 0 save 0 load 0 chid 0 -> chid 0
> [ 1696.780633] nouveau 0000:01:00.0: fifo:000003:03[   msvld]: 00000000: busy 0 faulted 0 chsw 0 save 0 load 0 chid 0 -> chid 0
> [ 1696.780689] nouveau 0000:01:00.0: fifo:000000:00[      gr]: 8006e005: busy 1 faulted 0 chsw 1 save 1 load 1 chid 5*-> chid 6
> [ 1696.780744] nouveau 0000:01:00.0: fifo:000000:00[      gr]: 8006e005: busy 1 faulted 0 chsw 1 save 1 load 1 chid 5*-> chid 6
> [ 1696.780795] nouveau 0000:01:00.0: fifo:000000:00[      gr]: triggering mmu fault on 0x00
> [ 1696.780835] nouveau 0000:01:00.0: fifo:000000:07[     ce2]: 00050005: busy 0 faulted 0 chsw 0 save 0 load 0 chid 5 -> chid 5
> [ 1696.780942] nouveau 0000:01:00.0: fifo:000000:00[      gr]: 00000100: mmu fault triggered
> [ 1696.780987] nouveau 0000:01:00.0: fifo:000000:00[      gr]: c006e005: busy 1 faulted 1 chsw 1 save 1 load 1 chid 5*-> chid 6
> [ 1696.781040] nouveau 0000:01:00.0: fifo:000000:0005:[Renderer[13701]] rc scheduled
>
> where I suspect ce2, is linked to PCE2.
>
> Is there a documentation that describes those "engines"?

CE is copy engine.
But this looks like an mmu fault on the GPU side, so some shader is
doing something wrong most likely.

Dave.