[PATCH] drm/amdgpu: Enable tunneling on high-priority compute queues

[Marek Olšák]

On Fri, Dec 8, 2023 at 9:57 AM Christian König <christian.koenig at amd.com>
wrote:

> Am 08.12.23 um 12:43 schrieb Friedrich Vock:
> > On 08.12.23 10:51, Christian König wrote:
> >> Well longer story short Alex and I have been digging up the
> >> documentation for this and as far as we can tell this isn't correct.
> > Huh. I initially talked to Marek about this, adding him in Cc.
>
> Yeah, from the userspace side all you need to do is to set the bit as
> far as I can tell.
>
> >>
> >> You need to do quite a bit more before you can turn on this feature.
> >> What userspace side do you refer to?
> > I was referring to the Mesa merge request I made
> > (https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26462).
> > If/When you have more details about what else needs to be done, feel
> > free to let me know.
>
> For example from the hardware specification explicitly states that the
> kernel driver should make sure that only one app/queue is using this at
> the same time. That might work for now since we should only have a
> single compute priority queue, but we are not 100% sure yet.
>

This is incorrect. While the hw documentation says it's considered
"unexpected programming", it also says that the hardware algorithm handles
it correctly and it describes what happens in this case: Tunneled waves
from different queues are treated as equal.

Marek
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