[Intel-gfx] [PATCH 8/8] drm/i915: Allow user to set cache at BO creation

[Andi Shyti]

Hi Fei,

> >>> To comply with the design that buffer objects shall have immutable
> >>> cache setting through out their life cycle, {set, get}_caching ioctl's
> >>> are no longer supported from MTL onward. With that change caching
> >>> policy can only be set at object creation time. The current code
> >>> applies a default (platform dependent) cache setting for all objects.
> >>> However this is not optimal for performance tuning. The patch extends
> >>> the existing gem_create uAPI to let user set PAT index for the object
> >>> at creation time.
> >>> The new extension is platform independent, so UMD's can switch to using
> >>> this extension for older platforms as well, while {set, get}_caching are
> >>> still supported on these legacy paltforms for compatibility reason.
> >>>
> >>> Cc: Chris Wilson <chris.p.wilson at linux.intel.com>
> >>> Cc: Matt Roper <matthew.d.roper at intel.com>
> >>> Cc: Andi Shyti <andi.shyti at linux.intel.com>
> >>> Signed-off-by: Fei Yang <fei.yang at intel.com>
> >>> Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
> >>
> >> because this is an API change, we need some more information
> >> here.
> >>
> >> First of all you need to CC the userspace guys that have been
> >> working on top of your series and get their ack's.
> >
> > Yes, and a link to a Mesa merge request which uses the uapi should be
> > included.
> 
> Working with Mesa team on this, stay tuned.
> 
> > IGTs should be ready to before we can merge. I glanced over igt-dev but
> > did not spot anything.
> 
> There is a IGT patch posted to gfx-internal-devel, titled "test/gem_create:
> exercise gem_create_ext_set_pat"

Any chance to have it ported upstream? It's OK even if it's not
merged (at least on my side) but some public interface testing is
needed.

If you do post it upstream you could add in the cover letter:

Test-with: <mail-id>

where the mail-id is referred to the upstream patch of the test.

Andi