Re: [Intel-gfx] [PATCH 1/5] drm: Use correct spinlock flavor in drm_vblank_get()

On Fri, 21 Feb 2014 21:03:31 +0200 ville.syrjala@linux.intel.com wrote:

From: Peter Hurley peter@hurleysoftware.com

The irq flags state is already established by the outer spin_lock_irqsave(); re-disabling irqs is redundant.

Signed-off-by: Peter Hurley peter@hurleysoftware.com

drivers/gpu/drm/drm_irq.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index c2676b5..baa12e7 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -882,13 +882,13 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) */ int drm_vblank_get(struct drm_device *dev, int crtc) {

• unsigned long irqflags, irqflags2;

• unsigned long irqflags; int ret = 0;

  spin_lock_irqsave(&dev->vbl_lock, irqflags); /* Going from 0->1 means we have to enable interrupts again */ if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {

• spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
  

• spin_lock(&dev->vblank_time_lock);
  

  if (!dev->vblank[crtc].enabled) { /* Enable vblank irqs under vblank_time_lock protection. * All vblank count & timestamp updates are held off

@@ -906,7 +906,7 @@ int drm_vblank_get(struct drm_device *dev, int crtc) drm_update_vblank_count(dev, crtc); } }

• spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
  

• spin_unlock(&dev->vblank_time_lock);
  

  } else { if (!dev->vblank[crtc].enabled) { atomic_dec(&dev->vblank[crtc].refcount);

Reviewed-by: Jesse Barnes jbarnes@virtuousgeek.org