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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

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. 

Also this would seem simpler:

if (SNB|IVB)
 mask = rc6 | rc6p | rc6pp;
else
 mask = rc6;

> +
> +		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
> 
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-- 
Ville Syrjälä
Intel OTC