Re: [PATCH] drm/i915: Sanitize the enable_ppgtt module option once

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Apr 23, 2014 at 11:37:46AM +0300, Jani Nikula wrote:
> On Tue, 22 Apr 2014, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > Otherwise we'll end up spamming dmesg on every context creation on snb
> > with vt-d enabled. This regression was introduced in
> >
> > commit 246cbfb5fb9a1ca0997fbb135464c1ff5bb9c549
> > Author: Ben Widawsky <benjamin.widawsky@intel.com>
> > Date:   Fri Dec 6 14:11:14 2013 -0800
> >
> >     drm/i915: Reorganize intel_enable_ppgtt
> >
> > References: https://lkml.org/lkml/2014/4/17/599
> > Cc: Alessandro Suardi <alessandro.suardi@gmail.com>
> > Cc: Ben Widawsky <ben@bwidawsk.net>
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 26 +++++++++++++++++++-------
> >  1 file changed, 19 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 0d514ff9b94c..47491c4a1181 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -34,25 +34,35 @@ static void gen8_setup_private_ppat(struct drm_i915_private *dev_priv);
> >  
> >  bool intel_enable_ppgtt(struct drm_device *dev, bool full)
> >  {
> > -	if (i915.enable_ppgtt == 0 || !HAS_ALIASING_PPGTT(dev))
> > +	if (i915.enable_ppgtt == 0)
> >  		return false;
> >  
> >  	if (i915.enable_ppgtt == 1 && full)
> >  		return false;
> >  
> > +	return true;
> > +}
> > +
> > +static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
> > +{
> > +	if (enable_ppgtt == 0 || !HAS_ALIASING_PPGTT(dev))
> > +		return 0;
> > +
> > +	if (i915.enable_ppgtt == 1)
> > +		return 1;
> > +
> > +	if (i915.enable_ppgtt == 2 && HAS_PPGTT(dev))
> > +		return 2;
> 
> You should probably either pass enable_ppgtt as parameter and use that
> exclusively, or not pass it and refer to i915.enable_ppgtt directly, but
> not mix them.

New patch on its way with Chris' comments also applied.
> 
> > +
> >  #ifdef CONFIG_INTEL_IOMMU
> >  	/* Disable ppgtt on SNB if VT-d is on. */
> >  	if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped) {
> >  		DRM_INFO("Disabling PPGTT because VT-d is on\n");
> > -		return false;
> > +		return 0;
> >  	}
> >  #endif
> >  
> > -	/* Full ppgtt disabled by default for now due to issues. */
> > -	if (full)
> > -		return HAS_PPGTT(dev) && (i915.enable_ppgtt == 2);
> > -	else
> > -		return HAS_ALIASING_PPGTT(dev);
> > +	return HAS_ALIASING_PPGTT(dev) ? 1 : 0;
> 
> 
> This conflicts in -fixes due to
> commit 8d214b7d9c45f4af23ce41b2bc74f79c44f760de
> Author: Ben Widawsky <benjamin.widawsky@linux.intel.com>
> Date:   Mon Mar 24 18:06:00 2014 -0700
> 
>     drm/i915: Allow full PPGTT with param override
> 
> Should I incorporate that in the conflict resolution for simplicity,
> letting 3.15 users also play with full ppgtt with the module param?

Yeah I guess it's easiest to just cherry-pick that one to -fixes, too.
-Daniel

> 
> 
> BR,
> Jani.
> 
> 
> >  }
> >  
> >  
> > @@ -1157,6 +1167,8 @@ int i915_gem_init_ppgtt(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> >  	int ret = 0;
> >  
> > +	i915.enable_ppgtt = sanitize_enable_ppgtt(dev, i915.enable_ppgtt);
> > +
> >  	ppgtt->base.dev = dev;
> >  	ppgtt->base.scratch = dev_priv->gtt.base.scratch;
> >  
> > -- 
> > 1.9.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch