[PATCH v10 2/2] drm/i915: Allow user to set cache at BO creation

[Andi Shyti]

> > > 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.
> > > 
> > > Test igt at gem_create@create_ext_set_pat posted at
> > > https://patchwork.freedesktop.org/series/117695/
> > > 
> > > Tested with https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22878
> > > 
> > > Signed-off-by: Fei Yang <fei.yang at intel.com>
> > > 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>
> > > Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
> > > Acked-by: Jordan Justen <jordan.l.justen at intel.com>
> > > Tested-by: Jordan Justen <jordan.l.justen at intel.com>
> > 
> > last call for comments and reviews on this patch. If nothing
> > comes I am going to push it tomorrow morning (Europe).
> > 
> > There is also a merge request from Mesa pending on this so that I
> > don't want to keep it hanging any longer.
> 
> No need to wait any longer with regard to feedback from Mesa.
> 
> I definitely was hoping for more consideration of the userspace
> request, but it's been decisively rejected. My ack was not readily
> given, but it stands.

Thanks, Jordan!

> -Jordan