Re: [PATCH v2 14/25] drm/i915: sanitize enable_rc6 option

[Imre Deak <imre.deak@intel.com>]

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On Wed, 2014-04-16 at 15:28 +0300, Ville Syrjälä wrote:
> On Mon, Apr 14, 2014 at 08:24:35PM +0300, Imre Deak wrote:
> > Atm, an invalid enable_rc6 module option will be silently ignored, so
> > emit an info message about it. Doing an early sanitization we can also
> > reuse intel_enable_rc6() in a follow-up patch to see if RC6 is actually
> > enabled. Currently the caller would have to filter a non-zero return
> > value based on the platform we are running on. For example on VLV with
> > i915.enable_rc6 set to 2, RC6 won't be enabled but atm
> > intel_enable_rc6() would still return 2 in this case.
> > 
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c | 27 ++++++++++++++++++++++++---
> >  1 file changed, 24 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index a56f6b1..89fe0a7 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -3262,15 +3262,29 @@ static void intel_print_rc6_info(struct drm_device *dev, u32 mode)
> >  		 (mode & GEN6_RC_CTL_RC6pp_ENABLE) ? "on" : "off");
> >  }
> >  
> > -int intel_enable_rc6(const struct drm_device *dev)
> > +static int sanitize_rc6_option(const struct drm_device *dev, int enable_rc6)
> >  {
> >  	/* No RC6 before Ironlake */
> >  	if (INTEL_INFO(dev)->gen < 5)
> >  		return 0;
> >  
> >  	/* Respect the kernel parameter if it is set */
> > -	if (i915.enable_rc6 >= 0)
> > -		return i915.enable_rc6;
> > +	if (enable_rc6 >= 0) {
> > +		int mask = 0;
> > +
> > +		if (IS_BROADWELL(dev) || IS_HASWELL(dev) ||
> > +		    IS_VALLEYVIEW(dev) || IS_IRONLAKE_M(dev))
> > +			mask = INTEL_RC6_ENABLE;
> > +		else if (INTEL_INFO(dev)->gen >= 6)
> > +			mask = INTEL_RC6_ENABLE | INTEL_RC6p_ENABLE |
> > +			       INTEL_RC6pp_ENABLE;
> 
> You forgot ILK. 

For desktop ILK intel_enable_gt_powersave() will keep RC6 disabled, so
the above is correct based on that.

> Also this would seem simpler:
> 
> if (SNB|IVB)
>  mask = rc6 | rc6p | rc6pp;
> else
>  mask = rc6;

Ok, can rewrite it with the above exception for desktop ILK.

--Imre

> 
> > +
> > +		if ((enable_rc6 & mask) != enable_rc6)
> > +			DRM_INFO("Adjusting RC6 mask to %d (requested %d, valid %d)\n",
> > +				 enable_rc6, enable_rc6 & mask, mask);
> > +
> > +		return enable_rc6 & mask;
> > +	}
> >  
> >  	/* Disable RC6 on Ironlake */
> >  	if (INTEL_INFO(dev)->gen == 5)
> > @@ -3282,6 +3296,11 @@ int intel_enable_rc6(const struct drm_device *dev)
> >  	return INTEL_RC6_ENABLE;
> >  }
> >  
> > +int intel_enable_rc6(const struct drm_device *dev)
> > +{
> > +	return i915.enable_rc6;
> > +}
> > +
> >  static void gen6_enable_rps_interrupts(struct drm_device *dev)
> >  {
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > @@ -4496,6 +4515,8 @@ static void intel_init_emon(struct drm_device *dev)
> >  
> >  void intel_init_gt_powersave(struct drm_device *dev)
> >  {
> > +	i915.enable_rc6 = sanitize_rc6_option(dev, i915.enable_rc6);
> > +
> >  	if (IS_VALLEYVIEW(dev))
> >  		valleyview_setup_pctx(dev);
> >  }
> > -- 
> > 1.8.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 


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