Re: [PATCH] drm/i915: Grab RPM wakeref around enabling vblank interrupts

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

On Fri, Oct 07, 2016 at 02:50:32PM +0100, Chris Wilson wrote:
> Whilst the vblank is configured to send an interrupt everytime, we need
> to keep the device awake to process those interrupts.

If we can enable vblanks the pipe will be active, and thus we can't
runtime suspend anyway. Also might_sleep() would be a problem.

> 
> Reported-by: Anssi Hannula <anssi.hannula@bitwise.fi>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=97985
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index bd6c8b0eeaef..bda7a27615a6 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2723,6 +2723,8 @@ static int i915_enable_vblank(struct drm_device *dev, unsigned int pipe)
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	unsigned long irqflags;
>  
> +	intel_runtime_pm_get(dev_priv);
> +
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	if (INTEL_INFO(dev)->gen >= 4)
>  		i915_enable_pipestat(dev_priv, pipe,
> @@ -2742,6 +2744,8 @@ static int ironlake_enable_vblank(struct drm_device *dev, unsigned int pipe)
>  	uint32_t bit = (INTEL_INFO(dev)->gen >= 7) ? DE_PIPE_VBLANK_IVB(pipe) :
>  						     DE_PIPE_VBLANK(pipe);
>  
> +	intel_runtime_pm_get(dev_priv);
> +
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	ilk_enable_display_irq(dev_priv, bit);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> @@ -2754,6 +2758,8 @@ static int valleyview_enable_vblank(struct drm_device *dev, unsigned int pipe)
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	unsigned long irqflags;
>  
> +	intel_runtime_pm_get(dev_priv);
> +
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	i915_enable_pipestat(dev_priv, pipe,
>  			     PIPE_START_VBLANK_INTERRUPT_STATUS);
> @@ -2767,6 +2773,8 @@ static int gen8_enable_vblank(struct drm_device *dev, unsigned int pipe)
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	unsigned long irqflags;
>  
> +	intel_runtime_pm_get(dev_priv);
> +
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	bdw_enable_pipe_irq(dev_priv, pipe, GEN8_PIPE_VBLANK);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> @@ -2787,6 +2795,8 @@ static void i915_disable_vblank(struct drm_device *dev, unsigned int pipe)
>  			      PIPE_VBLANK_INTERRUPT_STATUS |
>  			      PIPE_START_VBLANK_INTERRUPT_STATUS);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +
> +	intel_runtime_pm_put(dev_priv);
>  }
>  
>  static void ironlake_disable_vblank(struct drm_device *dev, unsigned int pipe)
> @@ -2799,6 +2809,8 @@ static void ironlake_disable_vblank(struct drm_device *dev, unsigned int pipe)
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	ilk_disable_display_irq(dev_priv, bit);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +
> +	intel_runtime_pm_put(dev_priv);
>  }
>  
>  static void valleyview_disable_vblank(struct drm_device *dev, unsigned int pipe)
> @@ -2810,6 +2822,8 @@ static void valleyview_disable_vblank(struct drm_device *dev, unsigned int pipe)
>  	i915_disable_pipestat(dev_priv, pipe,
>  			      PIPE_START_VBLANK_INTERRUPT_STATUS);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +
> +	intel_runtime_pm_put(dev_priv);
>  }
>  
>  static void gen8_disable_vblank(struct drm_device *dev, unsigned int pipe)
> @@ -2820,6 +2834,8 @@ static void gen8_disable_vblank(struct drm_device *dev, unsigned int pipe)
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  	bdw_disable_pipe_irq(dev_priv, pipe, GEN8_PIPE_VBLANK);
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +
> +	intel_runtime_pm_put(dev_priv);
>  }
>  
>  static bool
> -- 
> 2.9.3
> 
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-- 
Ville Syrjälä
Intel OTC
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