Re: [PATCH 2/2] drm/i915/gen8: Flip the 48b switch

Chris Wilson
2015-10-19T10:01:41Z

On Mon, Oct 19, 2015 at 11:44:12AM +0200, Daniel Vetter wrote:
> On Fri, Oct 16, 2015 at 01:23:41PM +0100, Michel Thierry wrote:
> > On 10/1/2015 2:16 PM, Daniel Vetter wrote:
> > >On Wed, Sep 30, 2015 at 03:36:19PM +0100, Michel Thierry wrote:
> > >>Use 48b addresses if hw supports it (i915.enable_ppgtt=3).
> > >>Update the sanitize_enable_ppgtt for 48 bit PPGTT mode.
> > >>
> > >>Note, aliasing PPGTT remains 32b only.
> > >>
> > >>v2: s/full_64b/full_48b/. (Akash)
> > >>v3: Add sanitize_enable_ppgtt changes until here. (Akash)
> > >>v4: Update param description (Chris)
> > >>
> > >>Cc: Akash Goel <akash.goel@intel.com>
> > >>Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > >>Signed-off-by: Michel Thierry <michel.thierry@intel.com>
> > >
> > >Queued for -next, thanks for the patch. Can you please ping someone from
> > >mesa to push the libdrm/mesa patches too?
> > >
> > >Cheers, Daniel
> > >
> >
> > Sorry I didn't report this earlier, but I just realized I can't find this
> > patch in the tree.
>
> Indeed I seem to have never pushed it. Sorry.
>
> > There's still the discussion of where to apply the 32-bit workaround and the
> > different behavior seen in mesa (not if it isn't needed)... but the code was
> > written to not require that flag in order to start using the 4-level page
> > translation.
>
> Queued for -next, thanks for the patch.

We never got an answer whether there was any impact on existing
userspace which is constained to 4GiB (where the last level of
pagetables are superfluous).
-Chris

--
Chris Wilson, Intel Open Source Technology Centre