Re: [PATCH v2] drm/xe/guc: Disable lite restore for MTL

[Kenneth Graunke <kenneth@whitecape.org>]

On Wednesday, March 19, 2025 1:20:40 PM Pacific Daylight Time John Harrison 
wrote:
> On 3/19/2025 10:28 AM, Zhanjun Dong wrote:
> > Lite restore for MTL is not POR for Xe, then disable it for MTL.
> 
> The point is that it is causing unexplained problems. And it is Xe as a
> whole that is not POR on MTL, not just lite restore. Hence no priority
> to investigate what is going wrong and how to fix it properly.
> 
> You should also reference the upstream bug that this is in response to.
> I think the tag is 'Closes:'?

Better yet, I managed to track down the missing invalidation.  I've just sent 
a patch to intel-xe@fd.o titled "drm/xe: Invalidate L3 read-only cachelines 
for geometry streams too" [1] which fixes the underlying issue and makes 
Firefox render correctly on Meteorlake with lite restore still enabled.  And 
probably fixes other bugs.

Assuming that patch is acceptable, I don't think we'll need to disable lite 
restore.  Which is certainly preferable!

--Ken

[1] https://lists.freedesktop.org/archives/intel-xe/2025-March/073997.html