Re: [PATCH v2 1/2] drm/i915/vlv: Remove wait for for punit to updates freq.

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

On Fri, May 08, 2015 at 08:43:10PM +0530, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> When GPU is idle on VLV, Request freq to punit should be good enough to
> get the voltage back to VNN. Also, make sure gfx clock force applies
> before requesting the freq fot vlv.
> 
> v2: Do forcewake before setting idle frequency (ville)
>     Update function comments to match the code (Deepak)
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75244
> suggested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 41 +++++++++++------------------------------
>  1 file changed, 11 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index a7516ed..3df929a 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4043,51 +4043,32 @@ static void valleyview_set_rps(struct drm_device *dev, u8 val)
>  	trace_intel_gpu_freq_change(intel_gpu_freq(dev_priv, val));
>  }
>  
> -/* vlv_set_rps_idle: Set the frequency to Rpn if Gfx clocks are down
> +/* vlv_set_rps_idle: Set the frequency to idle, if Gfx clocks are down
>   *
>   * * If Gfx is Idle, then
> - * 1. Mask Turbo interrupts
> - * 2. Bring up Gfx clock
> - * 3. Change the freq to Rpn and wait till P-Unit updates freq
> - * 4. Clear the Force GFX CLK ON bit so that Gfx can down
> - * 5. Unmask Turbo interrupts
> + * 1. Forcewake Media well.
> + * 2. Request idle freq.
> + * 3. Release Forcewake of Media well.
>  */
>  static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_device *dev = dev_priv->dev;
>  	u32 val = dev_priv->rps.idle_freq;
>  
> -	/* CHV and latest VLV don't need to force the gfx clock */
> -	if (IS_CHERRYVIEW(dev) || dev->pdev->revision >= 0xd) {
> +	/* CHV don't need to force the gfx clock */
> +	if (IS_CHERRYVIEW(dev)) {
>  		valleyview_set_rps(dev_priv->dev, val);
>  		return;
>  	}
>  
> -	/*
> -	 * When we are idle.  Drop to min voltage state.
> -	 */
> -
>  	if (dev_priv->rps.cur_freq <= val)
>  		return;
>  
> -	/* Mask turbo interrupt so that they will not come in between */
> -	I915_WRITE(GEN6_PMINTRMSK,
> -		   gen6_sanitize_rps_pm_mask(dev_priv, ~0));
> -
> -	vlv_force_gfx_clock(dev_priv, true);
> -
> -	dev_priv->rps.cur_freq = val;
> -
> -	vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ, val);
> -
> -	if (wait_for(((vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS))
> -				& GENFREQSTATUS) == 0, 100))
> -		DRM_ERROR("timed out waiting for Punit\n");
> -
> -	gen6_set_rps_thresholds(dev_priv, val);
> -	vlv_force_gfx_clock(dev_priv, false);
> -
> -	I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));
> +	/* Wake up the media well, as that takes a lot less
> +	 * power than the Render well. */
> +	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_MEDIA);
> +	valleyview_set_rps(dev_priv->dev, val);
> +	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_MEDIA);

_put

With that fixed this is:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  }
>  
>  void gen6_rps_busy(struct drm_i915_private *dev_priv)
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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