Re: [PATCH 40/44] drm/i915: Preserve current RPS frequency

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> Select idle frequency during initialisation, then reset the last known
> frequency when re-enabling. This allows us to preserve the user selected
> frequency across resets.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 658a75659657..98f0afa08332 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5092,6 +5092,7 @@ static void gen6_init_rps_frequencies(struct drm_i915_private *dev_priv)
>  	}
>  
>  	dev_priv->rps.idle_freq = dev_priv->rps.min_freq;
> +	dev_priv->rps.cur_freq = dev_priv->rps.idle_freq;
>  
>  	/* Preserve min/max settings in case of re-init */
>  	if (dev_priv->rps.max_freq_softlimit == 0)
> @@ -5108,6 +5109,15 @@ static void gen6_init_rps_frequencies(struct drm_i915_private *dev_priv)
>  	}
>  }
>  
> +static void reset_rps(struct drm_i915_private *dev_priv,
> +		      void (*set)(struct drm_i915_private *, u8))
> +{
> +	u8 freq = dev_priv->rps.cur_freq; /* force a reset */
> +	dev_priv->rps.power = -1;

I didn't find a spot where rps.power == -1 would cause
a reset.

For me it seems that gen6_init_rps_frequencies only handles
the enums thus with -1 we never will update the rps.power.

-Mika

> +	dev_priv->rps.cur_freq = -1;
> +	set(dev_priv, freq);
> +}
> +
>  /* See the Gen9_GT_PM_Programming_Guide doc for the below */
>  static void gen9_enable_rps(struct drm_i915_private *dev_priv)
>  {
> @@ -5144,8 +5154,7 @@ static void gen9_enable_rps(struct drm_i915_private *dev_priv)
>  	/* Leaning on the below call to gen6_set_rps to program/setup the
>  	 * Up/Down EI & threshold registers, as well as the RP_CONTROL,
>  	 * RP_INTERRUPT_LIMITS & RPNSWREQ registers */
> -	dev_priv->rps.power = HIGH_POWER; /* force a reset */
> -	gen6_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +	reset_rps(dev_priv, gen6_set_rps);
>  
>  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>  }
> @@ -5291,8 +5300,7 @@ static void gen8_enable_rps(struct drm_i915_private *dev_priv)
>  
>  	/* 6: Ring frequency + overclocking (our driver does this later */
>  
> -	dev_priv->rps.power = HIGH_POWER; /* force a reset */
> -	gen6_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +	reset_rps(dev_priv, gen6_set_rps);
>  
>  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>  }
> @@ -5385,8 +5393,7 @@ static void gen6_enable_rps(struct drm_i915_private *dev_priv)
>  		dev_priv->rps.max_freq = pcu_mbox & 0xff;
>  	}
>  
> -	dev_priv->rps.power = HIGH_POWER; /* force a reset */
> -	gen6_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +	reset_rps(dev_priv, gen6_set_rps);
>  
>  	rc6vids = 0;
>  	ret = sandybridge_pcode_read(dev_priv, GEN6_PCODE_READ_RC6VIDS, &rc6vids);
> @@ -5750,6 +5757,7 @@ static void valleyview_init_gt_powersave(struct drm_i915_private *dev_priv)
>  			 dev_priv->rps.min_freq);
>  
>  	dev_priv->rps.idle_freq = dev_priv->rps.min_freq;
> +	dev_priv->rps.cur_freq = dev_priv->rps.idle_freq;
>  
>  	/* Preserve min/max settings in case of re-init */
>  	if (dev_priv->rps.max_freq_softlimit == 0)
> @@ -5814,6 +5822,7 @@ static void cherryview_init_gt_powersave(struct drm_i915_private *dev_priv)
>  		  "Odd GPU freq values\n");
>  
>  	dev_priv->rps.idle_freq = dev_priv->rps.min_freq;
> +	dev_priv->rps.cur_freq = dev_priv->rps.idle_freq;
>  
>  	/* Preserve min/max settings in case of re-init */
>  	if (dev_priv->rps.max_freq_softlimit == 0)
> @@ -5922,7 +5931,7 @@ static void cherryview_enable_rps(struct drm_i915_private *dev_priv)
>  			 intel_gpu_freq(dev_priv, dev_priv->rps.idle_freq),
>  			 dev_priv->rps.idle_freq);
>  
> -	valleyview_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +	reset_rps(dev_priv, valleyview_set_rps);
>  
>  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>  }
> @@ -6002,16 +6011,7 @@ static void valleyview_enable_rps(struct drm_i915_private *dev_priv)
>  	DRM_DEBUG_DRIVER("GPLL enabled? %s\n", yesno(val & GPLLENABLE));
>  	DRM_DEBUG_DRIVER("GPU status: 0x%08x\n", val);
>  
> -	dev_priv->rps.cur_freq = (val >> 8) & 0xff;
> -	DRM_DEBUG_DRIVER("current GPU freq: %d MHz (%u)\n",
> -			 intel_gpu_freq(dev_priv, dev_priv->rps.cur_freq),
> -			 dev_priv->rps.cur_freq);
> -
> -	DRM_DEBUG_DRIVER("setting GPU freq to %d MHz (%u)\n",
> -			 intel_gpu_freq(dev_priv, dev_priv->rps.idle_freq),
> -			 dev_priv->rps.idle_freq);
> -
> -	valleyview_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +	reset_rps(dev_priv, valleyview_set_rps);
>  
>  	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
>  }
> -- 
> 2.8.1
>
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