Re: [PATCH v3 2/2] drm/xe: Clear GGTT in xe_bo_restore_kernel

[Matthew Brost <matthew.brost@intel.com>]

On Wed, Nov 13, 2024 at 12:55:35PM +0000, Matthew Auld wrote:
> On 06/11/2024 18:35, Matthew Brost wrote:
> > Part of what xe_bo_restore_kernel does, is restore BO's GGTT mappings
> > which may have been lost during a power state change. Missing is
> > restoring the GGTT entries without BO mappings to a known state (e.g.,
> > scratch pages). Update xe_bo_restore_kernel to clear the entire GGTT
> > before restoring BO's GGTT mappings.
> > 
> > v2:
> >   - Include missing local change of tile and id variable (CI)
> > v3:
> >   - Fixed kernel doc (CI)
> > 
> > Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
> > Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> > Cc: Matthew Auld <matthew.auld@intel.com>
> > Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> > Cc: <stable@vger.kernel.org> # v6.8+
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
>

Thanks for the review but I'm pretty sure this is breaking display... See
our CI runs, hard to exactly tell because of the instability there. I'm
thinking only the parts GGTT without nodes need to be cleared, i.e., do
what xe_ggtt_initial_clear does.

I am a little unsure how the display code restores it GGTT mappings
though as it appears that code bypasses BOs? Do you have any idea?

Matt