Re: [PATCH] drm/i915: add cherryview specfic forcewake in execlists_elsp_write

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

On Tue, Sep 09, 2014 at 07:14:16PM +0530, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> In chv, we have two power wells Render & Media. We need to use
> corresponsing forcewake count. If we dont follow this we are getting
> error "*ERROR*: Timed out waiting for forcewake old ack to clear" due to
> multiple entry into __vlv_force_wake_get.
> 
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lrc.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index bd1b28d..bafd38b 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -300,8 +300,18 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
>  	 * Instead, we do the runtime_pm_get/put when creating/destroying requests.
>  	 */
>  	spin_lock_irqsave(&dev_priv->uncore.lock, flags);
> -	if (dev_priv->uncore.forcewake_count++ == 0)
> -		dev_priv->uncore.funcs.force_wake_get(dev_priv, FORCEWAKE_ALL);
> +	if (IS_CHERRYVIEW(dev_priv->dev)) {
> +		if (dev_priv->uncore.fw_rendercount++ == 0)
> +			dev_priv->uncore.funcs.force_wake_get(dev_priv,
> +							      FORCEWAKE_RENDER);
> +		if (dev_priv->uncore.fw_mediacount++ == 0)
> +			dev_priv->uncore.funcs.force_wake_get(dev_priv,
> +							      FORCEWAKE_MEDIA);

This will wake both wells. Is that needed or should we just pick one
based on the ring?

> +	} else {
> +		if (dev_priv->uncore.forcewake_count++ == 0)
> +			dev_priv->uncore.funcs.force_wake_get(dev_priv,
> +							      FORCEWAKE_ALL);
> +	}
>  	spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
>  
>  	I915_WRITE(RING_ELSP(ring), desc[1]);
> @@ -315,8 +325,19 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
>  
>  	/* Release Force Wakeup (see the big comment above). */
>  	spin_lock_irqsave(&dev_priv->uncore.lock, flags);
> -	if (--dev_priv->uncore.forcewake_count == 0)
> -		dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
> +	if (IS_CHERRYVIEW(dev_priv->dev)) {
> +		if (--dev_priv->uncore.fw_rendercount == 0)
> +			dev_priv->uncore.funcs.force_wake_put(dev_priv,
> +							      FORCEWAKE_RENDER);
> +		if (--dev_priv->uncore.fw_mediacount == 0)
> +			dev_priv->uncore.funcs.force_wake_put(dev_priv,
> +							      FORCEWAKE_MEDIA);
> +	} else {
> +		if (--dev_priv->uncore.forcewake_count == 0)
> +			dev_priv->uncore.funcs.force_wake_put(dev_priv,
> +							      FORCEWAKE_ALL);
> +	}
> +
>  	spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
>  }
>  
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC