From 480c317a6ae634d777931eee54fadd2a50a2f650 Mon Sep 17 00:00:00 2001
From: Robert Noland <rnoland@2hip.net>
Date: Thu, 17 Jul 2008 14:01:04 -0400
Subject: [FreeBSD] drm_irq.c updates for vblank fixes.

---
 bsd-core/drmP.h    |  1 +
 bsd-core/drm_irq.c | 58 ++++++++++++++++++++++++++++++++----------------------
 2 files changed, 36 insertions(+), 23 deletions(-)

(limited to 'bsd-core')

diff --git a/bsd-core/drmP.h b/bsd-core/drmP.h
index b0a23e9c..2f2ffb3c 100644
--- a/bsd-core/drmP.h
+++ b/bsd-core/drmP.h
@@ -787,6 +787,7 @@ struct drm_device {
 
 	atomic_t	  context_flag;	/* Context swapping flag	   */
 	int		  last_context;	/* Last current context		   */
+	int		  vblank_disable_allowed;
 	wait_queue_head_t *vbl_queue;	/* vblank wait queue */
 	atomic_t	  *_vblank_count;	/* number of VBLANK interrupts */
 						/* (driver must alloc the right number of counters) */
diff --git a/bsd-core/drm_irq.c b/bsd-core/drm_irq.c
index a066cfc9..4b515ad8 100644
--- a/bsd-core/drm_irq.c
+++ b/bsd-core/drm_irq.c
@@ -81,9 +81,15 @@ static void vblank_disable_fn(void *arg)
 	}
 	callout_deactivate(&dev->vblank_disable_timer);
 
+	if (!dev->vblank_disable_allowed)
+		return;
+
 	for (i = 0; i < dev->num_crtcs; i++) {
 		if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
 		    dev->vblank_enabled[i]) {
+			DRM_DEBUG("disabling vblank on crtc %d\n", i);
+			dev->last_vblank[i] =
+			    dev->driver.get_vblank_counter(dev, i);
 			dev->driver.disable_vblank(dev, i);
 			dev->vblank_enabled[i] = 0;
 		}
@@ -181,6 +187,8 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 		atomic_set(&dev->vblank_refcount[i], 0);
 	}
 
+	dev->vblank_disable_allowed = 0;
+
 	return 0;
 
 err:
@@ -334,7 +342,6 @@ u32 drm_vblank_count(struct drm_device *dev, int crtc)
 
 void drm_update_vblank_count(struct drm_device *dev, int crtc)
 {
-	unsigned long irqflags;
 	u32 cur_vblank, diff;
 
 	if (dev->vblank_suspend[crtc])
@@ -348,7 +355,6 @@ void drm_update_vblank_count(struct drm_device *dev, int crtc)
 	 * a long time.
 	 */
 	cur_vblank = dev->driver.get_vblank_counter(dev, crtc);
-	DRM_SPINLOCK_IRQSAVE(&dev->vbl_lock, irqflags);
 	if (cur_vblank < dev->last_vblank[crtc]) {
 		if (cur_vblank == dev->last_vblank[crtc] - 1) {
 			diff = 0;
@@ -364,7 +370,9 @@ void drm_update_vblank_count(struct drm_device *dev, int crtc)
 		diff = cur_vblank - dev->last_vblank[crtc];
 	}
 	dev->last_vblank[crtc] = cur_vblank;
-	DRM_SPINUNLOCK_IRQRESTORE(&dev->vbl_lock, irqflags);
+
+	DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
+	    crtc, diff);
 
 	atomic_add(diff, &dev->_vblank_count[crtc]);
 }
@@ -382,8 +390,10 @@ int drm_vblank_get(struct drm_device *dev, int crtc)
 		ret = dev->driver.enable_vblank(dev, crtc);
 		if (ret)
 			atomic_dec(&dev->vblank_refcount[crtc]);
-		else
+		else {
 			dev->vblank_enabled[crtc] = 1;
+			drm_update_vblank_count(dev, crtc);
+		}
 	}
 	DRM_SPINUNLOCK_IRQRESTORE(&dev->vbl_lock, irqflags);
 
@@ -407,6 +417,8 @@ int drm_modeset_ctl(struct drm_device *dev, void *data,
 		    struct drm_file *file_priv)
 {
 	struct drm_modeset_ctl *modeset = data;
+	unsigned long irqflags;
+	u32 new, diff;
 	int crtc, ret = 0;
 
 	crtc = modeset->crtc;
@@ -417,27 +429,28 @@ int drm_modeset_ctl(struct drm_device *dev, void *data,
 
 	switch (modeset->cmd) {
 	case _DRM_PRE_MODESET:
-		dev->vblank_premodeset[crtc] =
-		    dev->driver.get_vblank_counter(dev, crtc);
-		dev->vblank_suspend[crtc] = 1;
+		DRM_SPINLOCK_IRQSAVE(&dev->vbl_lock, irqflags);
+		dev->vblank_disable_allowed = 1;
+		if (!dev->vblank_enabled[crtc]) {
+			dev->vblank_premodeset[crtc] =
+				dev->driver.get_vblank_counter(dev, crtc);
+			dev->vblank_suspend[crtc] = 1;
+		}
+		DRM_SPINUNLOCK_IRQRESTORE(&dev->vbl_lock, irqflags);
 		break;
 	case _DRM_POST_MODESET:
-		if (dev->vblank_suspend[crtc]) {
-			u32 new = dev->driver.get_vblank_counter(dev, crtc);
-
-			/* Compensate for spurious wraparound */
-			if (new < dev->vblank_premodeset[crtc]) {
-				atomic_sub(dev->max_vblank_count + new -
-				    dev->vblank_premodeset[crtc],
-				    &dev->_vblank_count[crtc]);
-				DRM_DEBUG("vblank_premodeset[%d]=0x%x, new=0x%x"
-				    " => _vblank_count[%d]-=0x%x\n", crtc,
-				    dev->vblank_premodeset[crtc], new,
-				    crtc, dev->max_vblank_count + new -
-				    dev->vblank_premodeset[crtc]);
-			}
+		DRM_SPINLOCK_IRQSAVE(&dev->vbl_lock, irqflags);
+		dev->vblank_disable_allowed = 1;
+		new = dev->driver.get_vblank_counter(dev, crtc);
+		if (dev->vblank_suspend[crtc] && !dev->vblank_enabled[crtc]) {
+			if (new > dev->vblank_premodeset[crtc])
+			    diff = dev->vblank_premodeset[crtc] - new;
+			else
+			    diff = new;
+			atomic_add(diff, &dev->_vblank_count[crtc]);
 		}
 		dev->vblank_suspend[crtc] = 0;
+		DRM_SPINUNLOCK_IRQRESTORE(&dev->vbl_lock, irqflags);
 		break;
 	default:
 		ret = EINVAL;
@@ -471,7 +484,6 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
 	if (crtc >= dev->num_crtcs)
 		return EINVAL;
 
-	drm_update_vblank_count(dev, crtc);
 	seq = drm_vblank_count(dev, crtc);
 
 	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
@@ -569,7 +581,7 @@ void drm_vbl_send_signals(struct drm_device *dev, int crtc )
 
 void drm_handle_vblank(struct drm_device *dev, int crtc)
 {
-	drm_update_vblank_count(dev, crtc);
+	atomic_inc(&dev->_vblank_count[crtc]);
 	DRM_WAKEUP(&dev->vbl_queue[crtc]);
 	drm_vbl_send_signals(dev, crtc);
 }
-- 
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