[Intel-gfx] [PATCH 3/2] drm/i915: Streamline VLV forcewake handling

[S, Deepak]

On 2/28/2014 1:37 AM, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> It occured to me that when we're trying to wake up both render
> and media wells on VLV, we might end up calling the low level
> force_wake_get/put two times even though one call would be
> enough. Make that happen by figuring out which wells really
> need to be woken up based on the forcewake counts.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/intel_uncore.c | 70 +++++++++++++++----------------------
>   1 file changed, 29 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index dacb751..4119ddc 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -251,16 +251,16 @@ void vlv_force_wake_get(struct drm_i915_private *dev_priv,
>   	unsigned long irqflags;
>
>   	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
> -	if (FORCEWAKE_RENDER & fw_engine) {
> -		if (dev_priv->uncore.fw_rendercount++ == 0)
> -			dev_priv->uncore.funcs.force_wake_get(dev_priv,
> -							FORCEWAKE_RENDER);
> -	}
> -	if (FORCEWAKE_MEDIA & fw_engine) {
> -		if (dev_priv->uncore.fw_mediacount++ == 0)
> -			dev_priv->uncore.funcs.force_wake_get(dev_priv,
> -							FORCEWAKE_MEDIA);
> -	}
> +
> +	if (fw_engine & FORCEWAKE_RENDER &&
> +	    dev_priv->uncore.fw_rendercount++ != 0)
> +		fw_engine &= ~FORCEWAKE_RENDER;
> +	if (fw_engine & FORCEWAKE_MEDIA &&
> +	    dev_priv->uncore.fw_mediacount++ != 0)
> +		fw_engine &= ~FORCEWAKE_MEDIA;

Should  we add WARN_ON? I think it will help us if we have forcewake 
count mismatch?

Other than this. Patch looks good.
Reviewed-by:Deepak S <deepak.s at intel.com>

> +	if (fw_engine)
> +		dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_engine);
>
>   	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
>   }
> @@ -272,19 +272,15 @@ void vlv_force_wake_put(struct drm_i915_private *dev_priv,
>
>   	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
>
> -	if (FORCEWAKE_RENDER & fw_engine) {
> -		WARN_ON(dev_priv->uncore.fw_rendercount == 0);
> -		if (--dev_priv->uncore.fw_rendercount == 0)
> -			dev_priv->uncore.funcs.force_wake_put(dev_priv,
> -							FORCEWAKE_RENDER);
> -	}
> +	if (fw_engine & FORCEWAKE_RENDER &&
> +	    --dev_priv->uncore.fw_rendercount != 0)
> +		fw_engine &= ~FORCEWAKE_RENDER;
> +	if (fw_engine & FORCEWAKE_MEDIA &&
> +	    --dev_priv->uncore.fw_mediacount != 0)
> +		fw_engine &= ~FORCEWAKE_MEDIA;
>
> -	if (FORCEWAKE_MEDIA & fw_engine) {
> -		WARN_ON(dev_priv->uncore.fw_mediacount == 0);
> -		if (--dev_priv->uncore.fw_mediacount == 0)
> -			dev_priv->uncore.funcs.force_wake_put(dev_priv,
> -							FORCEWAKE_MEDIA);
> -	}
> +	if (fw_engine)
> +		dev_priv->uncore.funcs.force_wake_put(dev_priv, fw_engine);
>
>   	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
>   }
> @@ -502,27 +498,19 @@ gen6_read##x(struct drm_i915_private *dev_priv, off_t reg, bool trace) { \
>   static u##x \
>   vlv_read##x(struct drm_i915_private *dev_priv, off_t reg, bool trace) { \
>   	unsigned fwengine = 0; \
> -	unsigned fwcount; \
>   	REG_READ_HEADER(x); \
> -	if (FORCEWAKE_VLV_RENDER_RANGE_OFFSET(reg)) {   \
> -		fwengine = FORCEWAKE_RENDER;            \
> -		fwcount = dev_priv->uncore.fw_rendercount;    \
> -	}                                               \
> -	else if (FORCEWAKE_VLV_MEDIA_RANGE_OFFSET(reg)) {       \
> -		fwengine = FORCEWAKE_MEDIA;             \
> -		fwcount = dev_priv->uncore.fw_mediacount;     \
> +	if (FORCEWAKE_VLV_RENDER_RANGE_OFFSET(reg)) { \
> +		if (dev_priv->uncore.fw_rendercount == 0) \
> +			fwengine = FORCEWAKE_RENDER; \
> +	} else if (FORCEWAKE_VLV_MEDIA_RANGE_OFFSET(reg)) { \
> +		if (dev_priv->uncore.fw_mediacount == 0) \
> +			fwengine = FORCEWAKE_MEDIA; \
>   	}  \
> -	if (fwengine != 0) {		\
> -		if (fwcount == 0) \
> -			(dev_priv)->uncore.funcs.force_wake_get(dev_priv, \
> -								fwengine); \
> -		val = __raw_i915_read##x(dev_priv, reg); \
> -		if (fwcount == 0) \
> -			(dev_priv)->uncore.funcs.force_wake_put(dev_priv, \
> -							fwengine); \
> -	} else { \
> -		val = __raw_i915_read##x(dev_priv, reg); \
> -	} \
> +	if (fwengine) \
> +		dev_priv->uncore.funcs.force_wake_get(dev_priv, fwengine); \
> +	val = __raw_i915_read##x(dev_priv, reg); \
> +	if (fwengine) \
> +		dev_priv->uncore.funcs.force_wake_put(dev_priv, fwengine); \
>   	REG_READ_FOOTER; \
>   }
>
>