[Mesa-dev] [PATCH] i965/icl: Allow headerless sampler messages for pre-emptable contexts

[Kenneth Graunke]

On Monday, August 20, 2018 10:26:29 AM PDT Anuj Phogat wrote:
> On Mon, Aug 20, 2018 at 12:18 AM Kenneth Graunke wrote:
[snip]
> > I don't know if people are trying to enable pre-emption during GPGPU
> > work on pre-Gen11.  If so, that probably will not work, and we'd either
> > need to avoid headerless messages (gross) or disable preemption (maybe
> > also bad...)
> >
> Why do you think it'll be problem for Pre-Gen11? I don't see a bit disallowing
> preemption+headerless message for pre-Gen11.

What's the more likely scenario?

Timeline A:

1. Preemption support was newly added; it didn't work with headerless
2. Somebody realized it was important and added a fix to make them work,
   but added it as a chicken bit that requires manual intervention.
3. They enabled the chicken bit by default, so things work right away.
4. They remove the chicken bit; the hardware just works.

Timeline B:

1. Preemption support was added and headerless works perfectly
2. Someone breaks headerless but adds a chicken bit to work around it
3. Someone enables the fix by default
4. They remove the chicken bit; the hardware just works.

IMHO, the first scenario is the most likely sequence of events.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: This is a digitally signed message part.
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20180820/94b97559/attachment.sig>