[Intel-gfx] [PATCH] drm/i915: fix sanitize_enable_ppgtt for full PPGTT

[Jesse Barnes]

On Thu, 26 Jun 2014 17:59:48 +0300
Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:

> On Wed, Jun 25, 2014 at 03:45:33PM -0700, Jesse Barnes wrote:
> > Apparently trinary logic is hard.  We were falling through all the forced
> > cases and simply enabling aliasing PPGTT or not based on hardware,
> > rather than full PPGTT if available.
> > 
> > References: https://bugs.freedesktop.org/show_bug.cgi?id=80083
> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index a4153ee..86521a7 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -69,7 +69,13 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
> >  		return 0;
> >  	}
> >  
> > -	return HAS_ALIASING_PPGTT(dev) ? 1 : 0;
> > +	/* Fall through to auto-detect */
> > +	if (HAS_PPGTT(dev))
> > +		return 2;
> > +	else if (HAS_ALIASING_PPGTT(dev))
> > +		return 1;
> > +
> > +	return 0;
> 
> I don't get it. This would just enable full ppgtt by default. But full
> ppgtt is still a bit broken so I don't think we want this.
> 
> The dmesg in the bug shows that ppgtt was forced off by the PCI revision
> check, so that part seems to have worked. Looks like the tests doesn't
> expect the batches to be accepted by the kernel, but the cmd parser is
> bypassed when ppgtt is disabled, so the test fails.

Yeah and I was testing on a platform that had PPGTT support, and
figured I had screwed up the PPGTT enable.  But I guess not, and we can
expect these tests to fail until we have the command parser enabled
everywhere.

-- 
Jesse Barnes, Intel Open Source Technology Center