Re: [PATCH v3] drm/i915: Added write-enable pte bit support

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Wed, 14 May 2014 00:30:34 +0200
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, May 13, 2014 at 03:05:24PM -0700, Jesse Barnes wrote:
> > On Tue, 11 Feb 2014 14:19:03 +0530
> > akash.goel@intel.com wrote:
> > 
> > > @@ -810,6 +815,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
> > >  		pt_vaddr[act_pte] =
> > >  			vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
> > >  				       cache_level, true);
> > > +
> > >  		if (++act_pte == I915_PPGTT_PT_ENTRIES) {
> > >  			kunmap_atomic(pt_vaddr);
> > >  			pt_vaddr = NULL;
> > 
> > Some extra whitespace here.
> > 
> > Otherwise:
> > Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> 
> Hm, looking at the patch again encoding this into the cache_level enum is
> fraught with fun. And due to IS_VLV aliasing chv this will blow up on chv
> very likely. My old idea was to eventually add a pte_flags param all over
> for this stuff with additional bits.

That works too; and yeah CHV is all different here isn't it.  But won't
it go through the gen8 paths anyway?

Ack on the cache_level abuse though; it's an implementation detail that
should be changed if/when this is properly exposed to userspace (or
maybe we shouldn't bother and just use CHV/BDW stuff going forward,
supporting a proper mprotect ioctl).

-- 
Jesse Barnes, Intel Open Source Technology Center