On Fri, Feb 20, 2015 at 09:09:02PM +0200, Imre Deak wrote:
> +static void intel_irq_set_state(struct drm_i915_private *dev_priv,
> +                             bool enabled)
> +{
> +     dev_priv->pm.irqs_enabled = enabled;
> +     /*
> +      * Before we unmask the interrupt or synchronize against it, make sure
> +      * that a corresponding interrupt handler running on another CPU sees
> +      * the updated irqs_enabled value.
> +      */
> +     smp_mb();

I would like a comment here to say something like: before powering down
the hardware make sure that we have no further access via pending
interrupt handlers. At the moment, I read the block comment above and
thought you were trying to imply something about the serialisation from
synchronize_irq() - but the only reason I can see you want sync_irq here
is to be sure that once the irq is disabled it is not going to run again.

> +     if (!enabled)
> +             synchronize_irq(dev_priv->dev->irq);
> +}

-- 
Chris Wilson, Intel Open Source Technology Centre
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