drm,radeon,i915: Use preempt_disable/enable_rt() where recommended

DRM folks identified the spots, so use them.

Signed-off-by: Mike Galbraith <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: linux-rt-users <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>

Author: umgwanakikbuti

drivers/gpu/drm/i915/i915_irq.c

@@ -847,6 +847,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
 	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -898,6 +899,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 

drivers/gpu/drm/radeon/radeon_display.c

@@ -1822,6 +1822,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
 	struct radeon_device *rdev = dev->dev_private;
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -1914,6 +1915,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	/* Decode into vertical and horizontal scanout position. */
 	*vpos = position & 0x1fff;