On Thu, Jun 16, 2016 at 05:19:49PM +0200, Michał Winiarski wrote:
> If the GPU load is low enough, it's possible that we'll be stuck at idle
> frequency rather than transition into softmin frequency requested by
> userspace.
> Since we assume that idle_freq <= min_freq_softlimit and
> valleyview_set_rps is already skipping write when
> requested_freq == cur_freq we can also remove vlv_set_idle function.
> 
> v2: Use intel_set_rps, drop vlv_set_idle
> 
> References: https://bugs.freedesktop.org/show_bug.cgi?id=89728
> Cc: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Imre Deak <imre.d...@intel.com>
> Signed-off-by: Michał Winiarski <michal.winiar...@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 33 +++++++--------------------------
>  1 file changed, 7 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 658a756..41c5d25 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4798,6 +4798,7 @@ static void valleyview_set_rps(struct drm_i915_private 
> *dev_priv, u8 val)
>       WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
>       WARN_ON(val > dev_priv->rps.max_freq);
>       WARN_ON(val < dev_priv->rps.min_freq);
> +     WARN_ON(val < dev_priv->rps.idle_freq);
>  
>       if (WARN_ONCE(IS_CHERRYVIEW(dev_priv) && (val & 1),
>                     "Odd GPU freq value\n"))
> @@ -4815,31 +4816,11 @@ static void valleyview_set_rps(struct 
> drm_i915_private *dev_priv, u8 val)
>       trace_intel_gpu_freq_change(intel_gpu_freq(dev_priv, val));
>  }
>  
> -/* vlv_set_rps_idle: Set the frequency to idle, if Gfx clocks are down
> - *
> - * * If Gfx is Idle, then
> - * 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)
> -{
> -     u32 val = dev_priv->rps.idle_freq;
> -
> -     if (dev_priv->rps.cur_freq <= val)
> -             return;
> -
> -     /* 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, val);
> -     intel_uncore_forcewake_put(dev_priv, FORCEWAKE_MEDIA);
> -}
> -
>  void gen6_rps_busy(struct drm_i915_private *dev_priv)
>  {
>       mutex_lock(&dev_priv->rps.hw_lock);
>       if (dev_priv->rps.enabled) {
> +             intel_set_rps(dev_priv, dev_priv->rps.min_freq_softlimit);
>               if (dev_priv->pm_rps_events & (GEN6_PM_RP_DOWN_EI_EXPIRED | 
> GEN6_PM_RP_UP_EI_EXPIRED))
>                       gen6_rps_reset_ei(dev_priv);
>               I915_WRITE(GEN6_PMINTRMSK,
> @@ -4852,10 +4833,7 @@ void gen6_rps_idle(struct drm_i915_private *dev_priv)
>  {
>       mutex_lock(&dev_priv->rps.hw_lock);
>       if (dev_priv->rps.enabled) {
> -             if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> -                     vlv_set_rps_idle(dev_priv);
> -             else
> -                     gen6_set_rps(dev_priv, dev_priv->rps.idle_freq);
> +             intel_set_rps(dev_priv, dev_priv->rps.idle_freq);
>               dev_priv->rps.last_adj = 0;
>               I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
>       }
> @@ -4905,8 +4883,11 @@ void gen6_rps_boost(struct drm_i915_private *dev_priv,
>  
>  void intel_set_rps(struct drm_i915_private *dev_priv, u8 val)
>  {
> -     if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> +     if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
> +             intel_uncore_forcewake_get(dev_priv, FORCEWAKE_MEDIA);
>               valleyview_set_rps(dev_priv, val);
> +             intel_uncore_forcewake_put(dev_priv, FORCEWAKE_MEDIA);

Why should we take the extra hit from waking the media well for every
RPS changes?

> +     }
>       else
>               gen6_set_rps(dev_priv, val);
>  }
> -- 
> 2.8.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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