From: Daniel Vetter Date: Thu, 4 Jul 2013 21:35:27 +0000 (+0200) Subject: drm/i915: queue work outside spinlock in hsw_pm_irq_handler X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2adbee62e00d869a30cb93ea2269e5ea26a9bbc4;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git drm/i915: queue work outside spinlock in hsw_pm_irq_handler And kill the comment about it. Queueing work is a barrier type event, no amount of locking will help in ordering things (as long as we queue the work after having updated all relevant data structures). Also, the queue_work works itself as a sufficient memory barrier. Again on the surface this is just a tiny micro-optimization to reduce the hold-time of dev_priv->irq_lock. But the better reason is that it reduces superficial locking and so makes it clearer what we actually need for correctness. Reviewed-by: Ben Widawsky Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index d4af11541287..04861995fe1b 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -969,9 +969,9 @@ static void hsw_pm_irq_handler(struct drm_i915_private *dev_priv, I915_WRITE(GEN6_PMIMR, dev_priv->rps.pm_iir); /* never want to mask useful interrupts. (also posting read) */ WARN_ON(I915_READ_NOTRACE(GEN6_PMIMR) & ~GEN6_PM_RPS_EVENTS); - /* TODO: if queue_work is slow, move it out of the spinlock */ - queue_work(dev_priv->wq, &dev_priv->rps.work); spin_unlock(&dev_priv->rps.lock); + + queue_work(dev_priv->wq, &dev_priv->rps.work); } if (pm_iir & PM_VEBOX_USER_INTERRUPT)