sync vblank code with linux

1 files changed, 937 insertions, 298 deletions

diff --git a/sys/dev/pci/drm/drm_irq.c b/sys/dev/pci/drm/drm_irq.c
index 43c1d90ff50..372fcdf6087 100644
--- a/sys/dev/pci/drm/drm_irq.c
+++ b/sys/dev/pci/drm/drm_irq.c
@@ -1,6 +1,16 @@
-/* $OpenBSD: drm_irq.c,v 1.43 2011/06/02 18:22:00 weerd Exp $ */
-/*-
- * Copyright 2003 Eric Anholt
+/**
+ * \file drm_irq.c
+ * IRQ support
+ *
+ * \author Rickard E. (Rik) Faith <faith@valinux.com>
+ * \author Gareth Hughes <gareth@valinux.com>
+ */
+
+/*
+ * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
+ *
+ * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
+ * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -17,18 +27,10 @@
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
- * ERIC ANHOLT BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
- * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- * Authors:
- *    Eric Anholt <anholt@FreeBSD.org>
- *
- */
-
-/** @file drm_irq.c
- * Support code for handling setup/teardown of interrupt handlers and
- * handing interrupt handlers off to the drivers.
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
  */
 
 #include <sys/workq.h>
@@ -36,11 +38,39 @@
 #include "drmP.h"
 #include "drm.h"
 
-void		drm_update_vblank_count(struct drm_device *, int);
-void		vblank_disable(void *);
-int		drm_queue_vblank_event(struct drm_device *, int,
-		    union drm_wait_vblank *, struct drm_file *);
-void		drm_handle_vblank_events(struct drm_device *, int);
+/* Access macro for slots in vblank timestamp ringbuffer. */
+#define vblanktimestamp(dev, crtc, count) ( \
+	(dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \
+	((count) % DRM_VBLANKTIME_RBSIZE)])
+
+/* Retry timestamp calculation up to 3 times to satisfy
+ * drm_timestamp_precision before giving up.
+ */
+#define DRM_TIMESTAMP_MAXRETRIES 3
+
+/* Threshold in nanoseconds for detection of redundant
+ * vblank irq in drm_handle_vblank(). 1 msec should be ok.
+ */
+#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
+
+void	 clear_vblank_timestamps(struct drm_device *, int);
+void	 vblank_disable_and_save(struct drm_device *, int);
+u32	 drm_get_last_vbltimestamp(struct drm_device *, int, struct timeval *,
+	     unsigned);
+void	 vblank_disable_fn(void *);
+int64_t	 timeval_to_ns(const struct timeval *);
+struct timeval ns_to_timeval(const int64_t);
+void	 drm_irq_vgaarb_nokms(void *, bool);
+struct timeval get_drm_timestamp(void);
+u32	 drm_vblank_count_and_time(struct drm_device *, int, struct timeval *);
+void	 send_vblank_event(struct drm_device *,
+	     struct drm_pending_vblank_event *, unsigned long,
+	     struct timeval *);
+void	 drm_update_vblank_count(struct drm_device *, int);
+void	 vblank_free(void *);
+int	 drm_queue_vblank_event(struct drm_device *, int,
+	     union drm_wait_vblank *, struct drm_file *);
+void	 drm_handle_vblank_events(struct drm_device *, int);
 
 #ifdef DRM_VBLANK_DEBUG
 #define DPRINTF(x...)	do { printf(x); } while(/* CONSTCOND */ 0)
@@ -48,6 +78,27 @@ void		drm_handle_vblank_events(struct drm_device *, int);
 #define DPRINTF(x...)	do { } while(/* CONSTCOND */ 0)
 #endif
 
+unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
+unsigned int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
+/*
+ * Default to use monotonic timestamps for wait-for-vblank and page-flip
+ * complete events.
+ */
+unsigned int drm_timestamp_monotonic = 1;
+
+/**
+ * Get interrupt from bus id.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_irq_busid structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * Finds the PCI device with the specified bus id and gets its IRQ number.
+ * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
+ * to that of the device that this DRM instance attached to.
+ */
 int
 drm_irq_by_busid(struct drm_device *dev, void *data, struct drm_file *file_priv)
 {
@@ -66,6 +117,283 @@ drm_irq_by_busid(struct drm_device *dev, void *data, struct drm_file *file_priv)
 	return 0;
 }
 
+/*
+ * Clear vblank timestamp buffer for a crtc.
+ */
+void
+clear_vblank_timestamps(struct drm_device *dev, int crtc)
+{
+	memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0,
+		DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval));
+}
+
+#define NSEC_PER_USEC	1000L
+#define NSEC_PER_SEC	1000000000L
+
+int64_t
+timeval_to_ns(const struct timeval *tv)
+{
+	return ((int64_t)tv->tv_sec * NSEC_PER_SEC) +
+		tv->tv_usec * NSEC_PER_USEC;
+}
+
+struct timeval
+ns_to_timeval(const int64_t nsec)
+{
+	struct timeval tv;
+	uint32_t rem;
+
+	if (nsec == 0) {
+		tv.tv_sec = 0;
+		tv.tv_usec = 0;
+		return (tv);
+	}
+
+	tv.tv_sec = nsec / NSEC_PER_SEC;
+	rem = nsec % NSEC_PER_SEC;
+	if (rem < 0) {
+		tv.tv_sec--;
+		rem += NSEC_PER_SEC;
+	}
+	tv.tv_usec = rem / 1000;
+	return (tv);
+}
+
+static inline int64_t
+abs64(int64_t x)
+{
+	return (x < 0 ? -x : x);
+}
+
+/*
+ * Disable vblank irq's on crtc, make sure that last vblank count
+ * of hardware and corresponding consistent software vblank counter
+ * are preserved, even if there are any spurious vblank irq's after
+ * disable.
+ */
+void
+vblank_disable_and_save(struct drm_device *dev, int crtc)
+{
+	u32 vblcount;
+	s64 diff_ns;
+	int vblrc;
+	struct timeval tvblank;
+	int count = DRM_TIMESTAMP_MAXRETRIES;
+
+	/* Prevent vblank irq processing while disabling vblank irqs,
+	 * so no updates of timestamps or count can happen after we've
+	 * disabled. Needed to prevent races in case of delayed irq's.
+	 */
+	mtx_enter(&dev->vblank_time_lock);
+
+	dev->driver->disable_vblank(dev, crtc);
+	dev->vblank_enabled[crtc] = 0;
+
+	/* No further vblank irq's will be processed after
+	 * this point. Get current hardware vblank count and
+	 * vblank timestamp, repeat until they are consistent.
+	 *
+	 * FIXME: There is still a race condition here and in
+	 * drm_update_vblank_count() which can cause off-by-one
+	 * reinitialization of software vblank counter. If gpu
+	 * vblank counter doesn't increment exactly at the leading
+	 * edge of a vblank interval, then we can lose 1 count if
+	 * we happen to execute between start of vblank and the
+	 * delayed gpu counter increment.
+	 */
+	do {
+		dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
+		vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
+	} while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
+
+	if (!count)
+		vblrc = 0;
+
+	/* Compute time difference to stored timestamp of last vblank
+	 * as updated by last invocation of drm_handle_vblank() in vblank irq.
+	 */
+	vblcount = atomic_read(&dev->_vblank_count[crtc]);
+	diff_ns = timeval_to_ns(&tvblank) -
+		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
+
+	/* If there is at least 1 msec difference between the last stored
+	 * timestamp and tvblank, then we are currently executing our
+	 * disable inside a new vblank interval, the tvblank timestamp
+	 * corresponds to this new vblank interval and the irq handler
+	 * for this vblank didn't run yet and won't run due to our disable.
+	 * Therefore we need to do the job of drm_handle_vblank() and
+	 * increment the vblank counter by one to account for this vblank.
+	 *
+	 * Skip this step if there isn't any high precision timestamp
+	 * available. In that case we can't account for this and just
+	 * hope for the best.
+	 */
+	if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
+		atomic_inc(&dev->_vblank_count[crtc]);
+//		smp_mb__after_atomic_inc();
+		DRM_WRITEMEMORYBARRIER();
+	}
+
+	/* Invalidate all timestamps while vblank irq's are off. */
+	clear_vblank_timestamps(dev, crtc);
+
+	mtx_leave(&dev->vblank_time_lock);
+}
+
+void
+vblank_disable_fn(void *arg)
+{
+	struct drm_device *dev = (struct drm_device *)arg;
+	int i;
+
+	if (!dev->vblank_disable_allowed)
+		return;
+
+	for (i = 0; i < dev->num_crtcs; i++) {
+		mtx_enter(&dev->vbl_lock);
+		if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
+		    dev->vblank_enabled[i]) {
+			DPRINTF("disabling vblank on crtc %d\n", i);
+			vblank_disable_and_save(dev, i);
+		}
+		mtx_leave(&dev->vbl_lock);
+	}
+}
+
+void
+drm_vblank_cleanup(struct drm_device *dev)
+{
+	/* Bail if the driver didn't call drm_vblank_init() */
+	if (dev->num_crtcs == 0)
+		return;
+
+	timeout_del(&dev->vblank_disable_timer);
+
+	vblank_disable_fn(dev);
+
+	free(dev->vbl_queue, M_DRM);
+	free(dev->_vblank_count, M_DRM);
+	free(dev->vblank_refcount, M_DRM);
+	free(dev->vblank_enabled, M_DRM);
+	free(dev->last_vblank, M_DRM);
+	free(dev->last_vblank_wait, M_DRM);
+	free(dev->vblank_inmodeset, M_DRM);
+	free(dev->_vblank_time, M_DRM);
+
+	dev->num_crtcs = 0;
+}
+
+int
+drm_vblank_init(struct drm_device *dev, int num_crtcs)
+{
+	int i, ret = -ENOMEM;
+
+	timeout_set(&dev->vblank_disable_timer, vblank_disable_fn,
+	    dev);
+	mtx_init(&dev->vbl_lock, IPL_TTY);
+	mtx_init(&dev->vblank_time_lock, IPL_NONE);
+
+	TAILQ_INIT(&dev->vbl_events);
+
+	dev->num_crtcs = num_crtcs;
+
+	dev->vbl_queue = malloc(sizeof(int) * num_crtcs,
+	    M_DRM, M_WAITOK);
+	if (!dev->vbl_queue)
+		goto err;
+
+	dev->_vblank_count = malloc(sizeof(atomic_t) * num_crtcs,
+	    M_DRM, M_WAITOK);
+	if (!dev->_vblank_count)
+		goto err;
+
+	dev->vblank_refcount = malloc(sizeof(atomic_t) * num_crtcs,
+	    M_DRM, M_WAITOK);
+	if (!dev->vblank_refcount)
+		goto err;
+
+	dev->vblank_enabled = malloc(num_crtcs * sizeof(int),
+	    M_DRM, M_ZERO | M_WAITOK);
+	if (!dev->vblank_enabled)
+		goto err;
+
+	dev->last_vblank = malloc(num_crtcs * sizeof(u32),
+	    M_DRM, M_ZERO | M_WAITOK);
+	if (!dev->last_vblank)
+		goto err;
+
+	dev->last_vblank_wait = malloc(num_crtcs * sizeof(u32),
+	    M_DRM, M_ZERO | M_WAITOK);
+	if (!dev->last_vblank_wait)
+		goto err;
+
+	dev->vblank_inmodeset = malloc(num_crtcs * sizeof(int),
+	    M_DRM, M_ZERO | M_WAITOK);
+	if (!dev->vblank_inmodeset)
+		goto err;
+
+	dev->_vblank_time = malloc(num_crtcs * DRM_VBLANKTIME_RBSIZE *
+	    sizeof(struct timeval), M_DRM, M_ZERO | M_WAITOK);
+	if (!dev->_vblank_time)
+		goto err;
+
+	DRM_DEBUG("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
+
+	/* Driver specific high-precision vblank timestamping supported? */
+	if (dev->driver->get_vblank_timestamp)
+		DRM_DEBUG("Driver supports precise vblank timestamp query.\n");
+	else
+		DRM_DEBUG("No driver support for vblank timestamp query.\n");
+
+	/* Zero per-crtc vblank stuff */
+	for (i = 0; i < num_crtcs; i++) {
+		atomic_set(&dev->_vblank_count[i], 0);
+		atomic_set(&dev->vblank_refcount[i], 0);
+	}
+
+	dev->vblank_disable_allowed = 0;
+	return 0;
+
+err:
+	drm_vblank_cleanup(dev);
+	return ret;
+}
+
+void
+drm_irq_vgaarb_nokms(void *cookie, bool state)
+{
+	struct drm_device *dev = cookie;
+
+#ifdef notyet
+	if (dev->driver->vgaarb_irq) {
+		dev->driver->vgaarb_irq(dev, state);
+		return;
+	}
+#endif
+
+	if (!dev->irq_enabled)
+		return;
+
+	if (state) {
+		if (dev->driver->irq_uninstall)
+			dev->driver->irq_uninstall(dev);
+	} else {
+		if (dev->driver->irq_preinstall)
+			dev->driver->irq_preinstall(dev);
+		if (dev->driver->irq_postinstall)
+			dev->driver->irq_postinstall(dev);
+	}
+}
+
+/**
+ * Install IRQ handler.
+ *
+ * \param dev DRM device.
+ *
+ * Initializes the IRQ related data. Installs the handler, calling the driver
+ * \c irq_preinstall() and \c irq_postinstall() functions
+ * before and after the installation.
+ */
 int
 drm_irq_install(struct drm_device *dev)
 {
@@ -102,6 +430,13 @@ err:
 	return (ret);
 }
 
+/**
+ * Uninstall the IRQ handler.
+ *
+ * \param dev DRM device.
+ *
+ * Calls the driver's \c irq_uninstall() function, and stops the irq.
+ */
 int
 drm_irq_uninstall(struct drm_device *dev)
 {
@@ -121,15 +456,15 @@ drm_irq_uninstall(struct drm_device *dev)
 	 * on them gets woken up. Also make sure we update state correctly
 	 * so that we can continue refcounting correctly.
 	 */
-	if (dev->vblank != NULL) {
-		mtx_enter(&dev->vblank->vb_lock);
-		for (i = 0; i < dev->vblank->vb_num; i++) {
-			wakeup(&dev->vblank->vb_crtcs[i]);
-			dev->vblank->vb_crtcs[i].vbl_enabled = 0;
-			dev->vblank->vb_crtcs[i].vbl_last =
+	if (dev->num_crtcs) {
+		mtx_enter(&dev->vbl_lock);
+		for (i = 0; i < dev->num_crtcs; i++) {
+			wakeup(&dev->vbl_queue[i]);
+			dev->vblank_enabled[i] = 0;
+			dev->last_vblank[i] =
 			    dev->driver->get_vblank_counter(dev, i);
 		}
-		mtx_leave(&dev->vblank->vb_lock);
+		mtx_leave(&dev->vbl_lock);
 	}
 
 	DRM_DEBUG("irq=%d\n", dev->irq);
@@ -139,6 +474,17 @@ drm_irq_uninstall(struct drm_device *dev)
 	return (0);
 }
 
+/**
+ * IRQ control ioctl.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_control structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * Calls irq_install() or irq_uninstall() according to \p arg.
+ */
 int
 drm_control(struct drm_device *dev, void *data, struct drm_file *file_priv)
 {
@@ -180,11 +526,11 @@ drm_control(struct drm_device *dev, void *data, struct drm_file *file_priv)
 void
 drm_calc_timestamping_constants(struct drm_crtc *crtc)
 {
-	int64_t linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
-	uint64_t dotclock;
+	s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
+	u64 dotclock;
 
 	/* Dot clock in Hz: */
-	dotclock = (uint64_t) crtc->hwmode.clock * 1000;
+	dotclock = (u64) crtc->hwmode.clock * 1000;
 
 	/* Fields of interlaced scanout modes are only halve a frame duration.
 	 * Double the dotclock to get halve the frame-/line-/pixelduration.
@@ -198,10 +544,10 @@ drm_calc_timestamping_constants(struct drm_crtc *crtc)
 		 * line duration, frame duration and pixel duration in
 		 * nanoseconds:
 		 */
-		pixeldur_ns = (int64_t)1000000000 / dotclock;
-		linedur_ns  = ((uint64_t)crtc->hwmode.crtc_htotal *
-		    1000000000) / dotclock;
-		framedur_ns = (int64_t) crtc->hwmode.crtc_vtotal * linedur_ns;
+		pixeldur_ns = (s64) 1000000000 / dotclock;
+		linedur_ns  = (s64) ((u64) crtc->hwmode.crtc_htotal *
+					      1000000000) / dotclock;
+		framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns;
 	} else
 		DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
 			  crtc->base.id);
@@ -210,10 +556,10 @@ drm_calc_timestamping_constants(struct drm_crtc *crtc)
 	crtc->linedur_ns  = linedur_ns;
 	crtc->framedur_ns = framedur_ns;
 
-	DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
+	DPRINTF("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
 		  crtc->base.id, crtc->hwmode.crtc_htotal,
 		  crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
-	DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
+	DPRINTF("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
 		  crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
 		  (int) linedur_ns, (int) pixeldur_ns);
 }
@@ -269,11 +615,10 @@ drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 					  unsigned flags,
 					  struct drm_crtc *refcrtc)
 {
-	printf("%s stub\n", __func__);
-	return EINVAL;
-#if 0
-	ktime_t stime, etime, mono_time_offset;
-	struct timeval tv_etime;
+	struct timeval stime, etime;
+#ifdef notyet
+	struct timeval mono_time_offset;
+#endif
 	struct drm_display_mode *mode;
 	int vbl_status, vtotal, vdisplay;
 	int vpos, hpos, i;
@@ -319,20 +664,24 @@ drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 		/* Disable preemption to make it very likely to
 		 * succeed in the first iteration even on PREEMPT_RT kernel.
 		 */
+#ifdef notyet
 		preempt_disable();
+#endif
 
 		/* Get system timestamp before query. */
-		stime = ktime_get();
+		getmicrouptime(&stime);
 
 		/* Get vertical and horizontal scanout pos. vpos, hpos. */
 		vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
 
 		/* Get system timestamp after query. */
-		etime = ktime_get();
+		getmicrouptime(&etime);
+#ifdef notyet
 		if (!drm_timestamp_monotonic)
 			mono_time_offset = ktime_get_monotonic_offset();
 
 		preempt_enable();
+#endif
 
 		/* Return as no-op if scanout query unsupported or failed. */
 		if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
@@ -341,7 +690,7 @@ drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 			return -EIO;
 		}
 
-		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
+		duration_ns = timeval_to_ns(&etime) - timeval_to_ns(&stime);
 
 		/* Accept result with <  max_error nsecs timing uncertainty. */
 		if (duration_ns <= (s64) *max_error)
@@ -388,20 +737,19 @@ drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 		vbl_status |= 0x8;
 	}
 
+#ifdef notyet
 	if (!drm_timestamp_monotonic)
 		etime = ktime_sub(etime, mono_time_offset);
+#endif
 
-	/* save this only for debugging purposes */
-	tv_etime = ktime_to_timeval(etime);
 	/* Subtract time delta from raw timestamp to get final
 	 * vblank_time timestamp for end of vblank.
 	 */
-	etime = ktime_sub_ns(etime, delta_ns);
-	*vblank_time = ktime_to_timeval(etime);
+	*vblank_time = ns_to_timeval(timeval_to_ns(&etime) - delta_ns);
 
-	DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
+	DPRINTF("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
 		  crtc, (int)vbl_status, hpos, vpos,
-		  (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
+		  (long)etime.tv_sec, (long)etime.tv_usec,
 		  (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
 		  (int)duration_ns/1000, i);
 
@@ -410,180 +758,348 @@ drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 		vbl_status |= DRM_VBLANKTIME_INVBL;
 
 	return vbl_status;
-#endif
 }
 
-void
-vblank_disable(void *arg)
+struct timeval
+get_drm_timestamp(void)
 {
-	struct drm_device	*dev = (struct drm_device*)arg;
-	struct drm_vblank_info	*vbl = dev->vblank;
-	struct drm_vblank	*crtc;
-	int			 i;
+	struct timeval now;
 
-	mtx_enter(&vbl->vb_lock);
-	for (i = 0; i < vbl->vb_num; i++) {
-		crtc = &vbl->vb_crtcs[i];
+	getmicrouptime(&now);
+#ifdef notyet
+	if (!drm_timestamp_monotonic)
+		now = ktime_sub(now, ktime_get_monotonic_offset());
+#endif
 
-		if (crtc->vbl_refs == 0 && crtc->vbl_enabled) {
-			DPRINTF("%s: disabling crtc %d\n", __func__, i);
-			crtc->vbl_last =
-			    dev->driver->get_vblank_counter(dev, i);
-			dev->driver->disable_vblank(dev, i);
-			crtc->vbl_enabled = 0;
-		}
-	}
-	mtx_leave(&vbl->vb_lock);
+	return (now);
 }
 
-void
-drm_vblank_cleanup(struct drm_device *dev)
+/**
+ * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
+ * vblank interval.
+ *
+ * @dev: DRM device
+ * @crtc: which crtc's vblank timestamp to retrieve
+ * @tvblank: Pointer to target struct timeval which should receive the timestamp
+ * @flags: Flags to pass to driver:
+ *         0 = Default.
+ *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
+ *
+ * Fetches the system timestamp corresponding to the time of the most recent
+ * vblank interval on specified crtc. May call into kms-driver to
+ * compute the timestamp with a high-precision GPU specific method.
+ *
+ * Returns zero if timestamp originates from uncorrected do_gettimeofday()
+ * call, i.e., it isn't very precisely locked to the true vblank.
+ *
+ * Returns non-zero if timestamp is considered to be very precise.
+ */
+u32
+drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
+			      struct timeval *tvblank, unsigned flags)
 {
-	if (dev->vblank == NULL)
-		return; /* not initialised */
+	int ret;
 
-	timeout_del(&dev->vblank->vb_disable_timer);
+	/* Define requested maximum error on timestamps (nanoseconds). */
+	int max_error = (int) drm_timestamp_precision * 1000;
 
-	vblank_disable(dev);
+	/* Query driver if possible and precision timestamping enabled. */
+	if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
+		ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
+							tvblank, flags);
+		if (ret > 0)
+			return (u32) ret;
+	}
 
-	drm_free(dev->vblank);
-	dev->vblank = NULL;
-	drm_free(dev->vblank_inmodeset);
-	dev->vblank_inmodeset = NULL;
+	/* GPU high precision timestamp query unsupported or failed.
+	 * Return current monotonic/gettimeofday timestamp as best estimate.
+	 */
+	*tvblank = get_drm_timestamp();
+
+	return 0;
 }
 
-int
-drm_vblank_init(struct drm_device *dev, int num_crtcs)
+/**
+ * drm_vblank_count - retrieve "cooked" vblank counter value
+ * @dev: DRM device
+ * @crtc: which counter to retrieve
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity.
+ */
+u32
+drm_vblank_count(struct drm_device *dev, int crtc)
 {
-	int	i;
+	return atomic_read(&dev->_vblank_count[crtc]);
+}
 
-	dev->vblank = malloc(sizeof(*dev->vblank) + (num_crtcs *
-	    sizeof(struct drm_vblank)), M_DRM,  M_WAITOK | M_CANFAIL | M_ZERO);
-	if (dev->vblank == NULL)
-		return (ENOMEM);
-	dev->vblank_inmodeset = malloc(num_crtcs * sizeof(int),
-	    M_DRM, M_WAITOK | M_ZERO);
-	dev->vblank->vb_num = num_crtcs;
-	mtx_init(&dev->vblank->vb_lock, IPL_TTY);
-	timeout_set(&dev->vblank->vb_disable_timer, vblank_disable, dev);
-	for (i = 0; i < num_crtcs; i++)
-		TAILQ_INIT(&dev->vblank->vb_crtcs[i].vbl_events);
+/**
+ * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
+ * and the system timestamp corresponding to that vblank counter value.
+ *
+ * @dev: DRM device
+ * @crtc: which counter to retrieve
+ * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity. Returns corresponding system timestamp of the time
+ * of the vblank interval that corresponds to the current value vblank counter
+ * value.
+ */
+u32
+drm_vblank_count_and_time(struct drm_device *dev, int crtc,
+			      struct timeval *vblanktime)
+{
+	u32 cur_vblank;
 
-	return (0);
+	/* Read timestamp from slot of _vblank_time ringbuffer
+	 * that corresponds to current vblank count. Retry if
+	 * count has incremented during readout. This works like
+	 * a seqlock.
+	 */
+	do {
+		cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
+		*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
+		DRM_READMEMORYBARRIER();
+	} while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
+
+	return cur_vblank;
 }
 
-u_int32_t
-drm_vblank_count(struct drm_device *dev, int crtc)
+void
+send_vblank_event(struct drm_device *dev,
+		struct drm_pending_vblank_event *e,
+		unsigned long seq, struct timeval *now)
 {
-	return (dev->vblank->vb_crtcs[crtc].vbl_count);
+	struct drm_file *file_priv = e->base.file_priv;
+//	WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
+	e->event.sequence = seq;
+	e->event.tv_sec = now->tv_sec;
+	e->event.tv_usec = now->tv_usec;
+
+	TAILQ_INSERT_TAIL(&file_priv->evlist, &e->base, link);
+	wakeup(&file_priv->evlist);
+	selwakeup(&file_priv->rsel);
+#if 0
+	trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
+					 e->event.sequence);
+#endif
 }
 
+/**
+ * drm_send_vblank_event - helper to send vblank event after pageflip
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ * @e: the event to send
+ *
+ * Updates sequence # and timestamp on event, and sends it to userspace.
+ * Caller must hold event lock.
+ */
+void
+drm_send_vblank_event(struct drm_device *dev, int crtc,
+		struct drm_pending_vblank_event *e)
+{
+	struct timeval now;
+	unsigned int seq;
+	if (crtc >= 0) {
+		seq = drm_vblank_count_and_time(dev, crtc, &now);
+	} else {
+		seq = 0;
+
+		now = get_drm_timestamp();
+	}
+	send_vblank_event(dev, e, seq, &now);
+}
+
+/**
+ * drm_update_vblank_count - update the master vblank counter
+ * @dev: DRM device
+ * @crtc: counter to update
+ *
+ * Call back into the driver to update the appropriate vblank counter
+ * (specified by @crtc).  Deal with wraparound, if it occurred, and
+ * update the last read value so we can deal with wraparound on the next
+ * call if necessary.
+ *
+ * Only necessary when going from off->on, to account for frames we
+ * didn't get an interrupt for.
+ *
+ * Note: caller must hold dev->vbl_lock since this reads & writes
+ * device vblank fields.
+ */
 void
 drm_update_vblank_count(struct drm_device *dev, int crtc)
 {
-	u_int32_t	cur_vblank, diff;
+	u32 cur_vblank, diff, tslot, rc;
+	struct timeval t_vblank;
 
 	/*
-	 * Interrupt was disabled prior to this call, so deal with counter wrap
-	 * note that we may have lost a full vb_max events if
-	 * the register is small or the interrupts were off for a long time.
+	 * Interrupts were disabled prior to this call, so deal with counter
+	 * wrap if needed.
+	 * NOTE!  It's possible we lost a full dev->max_vblank_count events
+	 * here if the register is small or we had vblank interrupts off for
+	 * a long time.
+	 *
+	 * We repeat the hardware vblank counter & timestamp query until
+	 * we get consistent results. This to prevent races between gpu
+	 * updating its hardware counter while we are retrieving the
+	 * corresponding vblank timestamp.
+	 */
+	do {
+		cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
+		rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
+	} while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
+
+	/* Deal with counter wrap */
+	diff = cur_vblank - dev->last_vblank[crtc];
+	if (cur_vblank < dev->last_vblank[crtc]) {
+		diff += dev->max_vblank_count;
+
+		DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
+			  crtc, dev->last_vblank[crtc], cur_vblank, diff);
+	}
+
+	DPRINTF("enabling vblank interrupts on crtc %d, missed %d\n",
+		  crtc, diff);
+
+	/* Reinitialize corresponding vblank timestamp if high-precision query
+	 * available. Skip this step if query unsupported or failed. Will
+	 * reinitialize delayed at next vblank interrupt in that case.
 	 */
-	cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
-	diff = cur_vblank - dev->vblank->vb_crtcs[crtc].vbl_last;
-	if (cur_vblank < dev->vblank->vb_crtcs[crtc].vbl_last)
-		diff += dev->vblank->vb_max;
+	if (rc) {
+		tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
+		vblanktimestamp(dev, crtc, tslot) = t_vblank;
+	}
 
-	dev->vblank->vb_crtcs[crtc].vbl_count += diff;
+//	smp_mb__before_atomic_inc();
+	atomic_add(diff, &dev->_vblank_count[crtc]);
+//	smp_mb__after_atomic_inc();
 }
 
+/**
+ * drm_vblank_get - get a reference count on vblank events
+ * @dev: DRM device
+ * @crtc: which CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * RETURNS
+ * Zero on success, nonzero on failure.
+ */
 int
 drm_vblank_get(struct drm_device *dev, int crtc)
 {
-	struct drm_vblank_info	*vbl = dev->vblank;
-	int			 ret = 0;
-
-	if (dev->irq_enabled == 0)
-		return (EINVAL);
-
-	mtx_enter(&vbl->vb_lock);
-	DPRINTF("%s: %d refs = %d\n", __func__, crtc,
-	    vbl->vb_crtcs[crtc].vbl_refs);
-	vbl->vb_crtcs[crtc].vbl_refs++;
-	if (vbl->vb_crtcs[crtc].vbl_refs == 1 &&
-	    vbl->vb_crtcs[crtc].vbl_enabled == 0) {
-		if ((ret = dev->driver->enable_vblank(dev, crtc)) == 0) {
-			vbl->vb_crtcs[crtc].vbl_enabled = 1;
-			drm_update_vblank_count(dev, crtc);
-		} else {
-			vbl->vb_crtcs[crtc].vbl_refs--;
+	int ret = 0;
+
+	mtx_enter(&dev->vbl_lock);
+	/* Going from 0->1 means we have to enable interrupts again */
+	if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
+		mtx_enter(&dev->vblank_time_lock);
+		if (!dev->vblank_enabled[crtc]) {
+			/* Enable vblank irqs under vblank_time_lock protection.
+			 * All vblank count & timestamp updates are held off
+			 * until we are done reinitializing master counter and
+			 * timestamps. Filtercode in drm_handle_vblank() will
+			 * prevent double-accounting of same vblank interval.
+			 */
+			ret = dev->driver->enable_vblank(dev, crtc);
+			DPRINTF("enabling vblank on crtc %d, ret: %d\n",
+				  crtc, ret);
+			if (ret)
+				atomic_dec(&dev->vblank_refcount[crtc]);
+			else {
+				dev->vblank_enabled[crtc] = 1;
+				drm_update_vblank_count(dev, crtc);
+			}
+		}
+		mtx_leave(&dev->vblank_time_lock);
+	} else {
+		if (!dev->vblank_enabled[crtc]) {
+			atomic_dec(&dev->vblank_refcount[crtc]);
+			ret = -EINVAL;
 		}
-
 	}
-	mtx_leave(&vbl->vb_lock);
+	mtx_leave(&dev->vbl_lock);
 
-	return (ret);
+	return ret;
 }
 
+/**
+ * drm_vblank_put - give up ownership of vblank events
+ * @dev: DRM device
+ * @crtc: which counter to give up
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
+ */
 void
 drm_vblank_put(struct drm_device *dev, int crtc)
 {
-	mtx_enter(&dev->vblank->vb_lock);
-	/* Last user schedules disable */
-	DPRINTF("%s: %d  refs = %d\n", __func__, crtc,
-	    dev->vblank->vb_crtcs[crtc].vbl_refs);
-	KASSERT(dev->vblank->vb_crtcs[crtc].vbl_refs > 0);
-	if (--dev->vblank->vb_crtcs[crtc].vbl_refs == 0)
-		timeout_add_sec(&dev->vblank->vb_disable_timer, 5);
-	mtx_leave(&dev->vblank->vb_lock);
+	BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
+
+	/* Last user schedules interrupt disable */
+	if ((--dev->vblank_refcount[crtc] == 0) &&
+	    (drm_vblank_offdelay > 0))
+		timeout_add_msec(&dev->vblank_disable_timer, drm_vblank_offdelay);
 }
 
-void drm_vblank_off(struct drm_device *dev, int crtc)
+/**
+ * drm_vblank_off - disable vblank events on a CRTC
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ *
+ * Caller must hold event lock.
+ */
+void
+drm_vblank_off(struct drm_device *dev, int crtc)
 {
-	printf("%s stub\n", __func__);
-#ifdef notyet
-	struct drm_pending_vblank_event *e, *t;
+	struct drmevlist *list;
+	struct drm_pending_event *ev, *tmp;
+	struct drm_pending_vblank_event *vev;
 	struct timeval now;
 	unsigned int seq;
 
-	mtx_enter(&dev->vblank->vb_lock);
+	mtx_enter(&dev->vbl_lock);
 	vblank_disable_and_save(dev, crtc);
-	mtx_enter(&dev->event_lock);
-	wakeup(&dev->_vblank_count[crtc]);
+	wakeup(&dev->vbl_queue[crtc]);
 
+	list = &dev->vbl_events;
 	/* Send any queued vblank events, lest the natives grow disquiet */
 	seq = drm_vblank_count_and_time(dev, crtc, &now);
-	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
-		if (e->pipe != crtc)
+
+	mtx_enter(&dev->event_lock);
+	for (ev = TAILQ_FIRST(list); ev != TAILQ_END(list); ev = tmp) {
+		tmp = TAILQ_NEXT(ev, link);
+
+		vev = (struct drm_pending_vblank_event *)ev;
+
+		if (vev->pipe != crtc)
 			continue;
 		DRM_DEBUG("Sending premature vblank event on disable: \
 			  wanted %d, current %d\n",
-			  e->event.sequence, seq);
-
-		e->event.sequence = seq;
-		e->event.tv_sec = now.tv_sec;
-		e->event.tv_usec = now.tv_usec;
-		drm_vblank_put(dev, e->pipe);
-		list_move_tail(&e->base.link, &e->base.file_priv->event_list);
-		drm_event_wakeup(&e->base);
-		CTR3(KTR_DRM, "vblank_event_delivered %d %d %d",
-		    e->base.pid, e->pipe, e->event.sequence);
+			  vev->event.sequence, seq);
+		TAILQ_REMOVE(list, ev, link);
+		drm_vblank_put(dev, vev->pipe);
+		send_vblank_event(dev, vev, seq, &now);
 	}
-
 	mtx_leave(&dev->event_lock);
-	mtx_leave(&dev->vblank->vb_lock);
-#endif
+
+	mtx_leave(&dev->vbl_lock);
 }
 
 /**
  * drm_vblank_pre_modeset - account for vblanks across mode sets
  * @dev: DRM device
  * @crtc: CRTC in question
- * @post: post or pre mode set?
  *
  * Account for vblank events across mode setting events, which will likely
  * reset the hardware frame counter.
  */
-void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
+void
+drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 {
 	/* vblank is not initialized (IRQ not installed ?) */
 	if (!dev->num_crtcs)
@@ -602,13 +1118,13 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 	}
 }
 
-void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
+void
+drm_vblank_post_modeset(struct drm_device *dev, int crtc)
 {
-
 	if (dev->vblank_inmodeset[crtc]) {
-		mtx_enter(&dev->vblank->vb_lock);
+		mtx_enter(&dev->vbl_lock);
 		dev->vblank_disable_allowed = 1;
-		mtx_leave(&dev->vblank->vb_lock);
+		mtx_leave(&dev->vbl_lock);
 
 		if (dev->vblank_inmodeset[crtc] & 0x2)
 			drm_vblank_put(dev, crtc);
@@ -617,214 +1133,337 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
 	}
 }
 
+/**
+ * drm_modeset_ctl - handle vblank event counter changes across mode switch
+ * @DRM_IOCTL_ARGS: standard ioctl arguments
+ *
+ * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
+ * ioctls around modesetting so that any lost vblank events are accounted for.
+ *
+ * Generally the counter will reset across mode sets.  If interrupts are
+ * enabled around this call, we don't have to do anything since the counter
+ * will have already been incremented.
+ */
 int
-drm_modeset_ctl(struct drm_device *dev, void *data, struct drm_file *file_priv)
+drm_modeset_ctl(struct drm_device *dev, void *data,
+		    struct drm_file *file_priv)
 {
-	struct drm_modeset_ctl	*modeset = data;
-	struct drm_vblank	*vbl;
-	int			 crtc, ret = 0;
+	struct drm_modeset_ctl *modeset = data;
+	unsigned int crtc;
 
-	/* not initialised yet, just noop */
-	if (dev->vblank == NULL)
-		return (0);
+	/* If drm_vblank_init() hasn't been called yet, just no-op */
+	if (!dev->num_crtcs)
+		return 0;
 
-	crtc = modeset->crtc;
-	if (crtc >= dev->vblank->vb_num || crtc < 0)
-		return (EINVAL);
+	/* KMS drivers handle this internally */
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		return 0;
 
-	vbl = &dev->vblank->vb_crtcs[crtc];
+	crtc = modeset->crtc;
+	if (crtc >= dev->num_crtcs)
+		return -EINVAL;
 
-	/*
-	 * If interrupts are enabled/disabled between calls to this ioctl then
-	 * it can get nasty. So just grab a reference so that the interrupts
-	 * keep going through the modeset
-	 */
 	switch (modeset->cmd) {
 	case _DRM_PRE_MODESET:
-		DPRINTF("%s: pre modeset on %d\n", __func__, crtc);
-		if (vbl->vbl_inmodeset == 0) {
-			mtx_enter(&dev->vblank->vb_lock);
-			vbl->vbl_inmodeset = 0x1;
-			mtx_leave(&dev->vblank->vb_lock);
-			if (drm_vblank_get(dev, crtc) == 0)
-				vbl->vbl_inmodeset |= 0x2;
-		}
+		drm_vblank_pre_modeset(dev, crtc);
 		break;
 	case _DRM_POST_MODESET:
-		DPRINTF("%s: post modeset on %d\n", __func__, crtc);
-		if (vbl->vbl_inmodeset) {
-			if (vbl->vbl_inmodeset & 0x2)
-				drm_vblank_put(dev, crtc);
-			vbl->vbl_inmodeset = 0;
-		}
+		drm_vblank_post_modeset(dev, crtc);
 		break;
 	default:
-		ret = EINVAL;
-		break;
+		return -EINVAL;
 	}
 
-	return (ret);
+	return 0;
 }
 
-int
-drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_priv)
+void
+vblank_free(void *ptr)
 {
-	struct timeval		 now;
-	union drm_wait_vblank	*vblwait = data;
-	int			 ret, flags, crtc, seq;
+	free(ptr, M_DRM);
+}
 
-	if (!dev->irq_enabled || dev->vblank == NULL ||
-	    vblwait->request.type & _DRM_VBLANK_SIGNAL)
-		return (EINVAL);
+int
+drm_queue_vblank_event(struct drm_device *dev, int pipe,
+				  union drm_wait_vblank *vblwait,
+				  struct drm_file *file_priv)
+{
+	struct drm_pending_vblank_event *e;
+	struct timeval now;
+	unsigned int seq;
+	int ret;
 
-	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
-	crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
+	e = malloc(sizeof *e, M_DRM, M_ZERO | M_WAITOK);
+	if (e == NULL) {
+		ret = -ENOMEM;
+		goto err_put;
+	}
 
-	if (crtc >= dev->vblank->vb_num)
-		return (EINVAL);
+	e->pipe = pipe;
+	e->base.pid = DRM_CURRENTPID;
+	e->event.base.type = DRM_EVENT_VBLANK;
+	e->event.base.length = sizeof e->event;
+	e->event.user_data = vblwait->request.signal;
+	e->base.event = &e->event.base;
+	e->base.file_priv = file_priv;
+	e->base.destroy = (void (*) (struct drm_pending_event *)) vblank_free;
 
-	if ((ret = drm_vblank_get(dev, crtc)) != 0)
-		return (ret);
-	seq = drm_vblank_count(dev, crtc);
+	mtx_enter(&dev->event_lock);
 
-	if (vblwait->request.type & _DRM_VBLANK_RELATIVE) {
-		vblwait->request.sequence += seq;
-		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
+	if (file_priv->event_space < sizeof e->event) {
+		ret = -EBUSY;
+		goto err_unlock;
 	}
 
-	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
-	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
-	    (seq - vblwait->request.sequence) <= (1<<23)) {
+	file_priv->event_space -= sizeof e->event;
+	seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
+	    (seq - vblwait->request.sequence) <= (1 << 23)) {
 		vblwait->request.sequence = seq + 1;
+		vblwait->reply.sequence = vblwait->request.sequence;
 	}
 
-	if (flags & _DRM_VBLANK_EVENT)
-		return (drm_queue_vblank_event(dev, crtc, vblwait, file_priv));
+	DPRINTF("event on vblank count %d, current %d, crtc %d\n",
+		  vblwait->request.sequence, seq, pipe);
 
-	DPRINTF("%s: %d waiting on %d, current %d\n", __func__, crtc,
-	     vblwait->request.sequence, drm_vblank_count(dev, crtc));
-	DRM_WAIT_ON(ret, &dev->vblank->vb_crtcs[crtc], &dev->vblank->vb_lock,
-	    3 * hz, "drmvblq", ((drm_vblank_count(dev, crtc) -
-	    vblwait->request.sequence) <= (1 << 23)) || dev->irq_enabled == 0);
+#if 0
+	trace_drm_vblank_event_queued(current->pid, pipe,
+				      vblwait->request.sequence);
+#endif
 
-	microtime(&now);
-	vblwait->reply.tval_sec = now.tv_sec;
-	vblwait->reply.tval_usec = now.tv_usec;
-	vblwait->reply.sequence = drm_vblank_count(dev, crtc);
-	DPRINTF("%s: %d done waiting, seq = %d\n", __func__, crtc,
-	    vblwait->reply.sequence);
+	e->event.sequence = vblwait->request.sequence;
+	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
+		drm_vblank_put(dev, pipe);
+		send_vblank_event(dev, e, seq, &now);
+		vblwait->reply.sequence = seq;
+	} else {
+		/* drm_handle_vblank_events will call drm_vblank_put */
+		TAILQ_INSERT_TAIL(&dev->vbl_events, &e->base, link);
+		vblwait->reply.sequence = vblwait->request.sequence;
+	}
 
-	drm_vblank_put(dev, crtc);
-	return (ret);
+	mtx_leave(&dev->event_lock);
+
+	return 0;
+
+err_unlock:
+	mtx_leave(&dev->event_lock);
+	free(e, M_DRM);
+err_put:
+	drm_vblank_put(dev, pipe);
+	return ret;
 }
 
+/**
+ * Wait for VBLANK.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param data user argument, pointing to a drm_wait_vblank structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * This function enables the vblank interrupt on the pipe requested, then
+ * sleeps waiting for the requested sequence number to occur, and drops
+ * the vblank interrupt refcount afterwards. (vblank irq disable follows that
+ * after a timeout with no further vblank waits scheduled).
+ */
 int
-drm_queue_vblank_event(struct drm_device *dev, int crtc,
-    union drm_wait_vblank *vblwait, struct drm_file *file_priv)
+drm_wait_vblank(struct drm_device *dev, void *data,
+		    struct drm_file *file_priv)
 {
-	struct drm_pending_vblank_event	*vev;
-	struct timeval			 now;
-	u_int				 seq;
+	union drm_wait_vblank *vblwait = data;
+	int ret;
+	unsigned int flags, seq, crtc, high_crtc;
 
+	if (!dev->irq_enabled)
+		return -EINVAL;
 
-	vev = drm_calloc(1, sizeof(*vev));
-	if (vev == NULL)
-		return (ENOMEM);
-
-	vev->event.base.type = DRM_EVENT_VBLANK;
-	vev->event.base.length = sizeof(vev->event);
-	vev->event.user_data = vblwait->request.signal;
-	vev->base.event = &vev->event.base;
-	vev->base.file_priv = file_priv;
-	vev->base.destroy = (void (*) (struct drm_pending_event *))drm_free;
-
-	microtime(&now);
+	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
+		return -EINVAL;
 
-	mtx_enter(&dev->event_lock);
-	if (file_priv->event_space < sizeof(vev->event)) {
-		mtx_leave(&dev->event_lock);
-		drm_free(vev);
-		return (ENOMEM);
+	if (vblwait->request.type &
+	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
+		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
+			  vblwait->request.type,
+			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+			   _DRM_VBLANK_HIGH_CRTC_MASK));
+		return -EINVAL;
 	}
 
+	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
+	high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
+	if (high_crtc)
+		crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
+	else
+		crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
+	if (crtc >= dev->num_crtcs)
+		return -EINVAL;
 
+	ret = drm_vblank_get(dev, crtc);
+	if (ret) {
+		DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
+		return ret;
+	}
 	seq = drm_vblank_count(dev, crtc);
-	file_priv->event_space -= sizeof(vev->event);
 
-	DPRINTF("%s: queueing event %d on crtc %d\n", __func__, seq, crtc);
+	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
+	case _DRM_VBLANK_RELATIVE:
+		vblwait->request.sequence += seq;
+		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
+	case _DRM_VBLANK_ABSOLUTE:
+		break;
+	default:
+		ret = -EINVAL;
+		goto done;
+	}
 
-	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
-	    (seq - vblwait->request.sequence) <= (1 << 23)) {
+	if (flags & _DRM_VBLANK_EVENT) {
+		/* must hold on to the vblank ref until the event fires
+		 * drm_vblank_put will be called asynchronously
+		 */
+		return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
+	}
+
+	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
+	    (seq - vblwait->request.sequence) <= (1<<23)) {
 		vblwait->request.sequence = seq + 1;
-		vblwait->reply.sequence = vblwait->request.sequence;
 	}
 
-	vev->event.sequence = vblwait->request.sequence;
-	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
-		vev->event.tv_sec = now.tv_sec;
-		vev->event.tv_usec = now.tv_usec;
-		DPRINTF("%s: already passed, dequeuing: crtc %d, value %d\n",
-		    __func__, crtc, seq);
-		drm_vblank_put(dev, crtc);
-		TAILQ_INSERT_TAIL(&file_priv->evlist, &vev->base, link);
-		wakeup(&file_priv->evlist);
-		selwakeup(&file_priv->rsel);
+	DPRINTF("waiting on vblank count %d, crtc %d\n",
+		  vblwait->request.sequence, crtc);
+	dev->last_vblank_wait[crtc] = vblwait->request.sequence;
+	DRM_WAIT_ON(ret, &dev->vbl_queue[crtc], &dev->vbl_lock, 3 * hz,
+		    "drmvblq", (((drm_vblank_count(dev, crtc) -
+		       vblwait->request.sequence) <= (1 << 23)) ||
+		     !dev->irq_enabled));
+
+	if (ret != -EINTR) {
+		struct timeval now;
+
+		vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
+		vblwait->reply.tval_sec = now.tv_sec;
+		vblwait->reply.tval_usec = now.tv_usec;
+
+		DPRINTF("returning %d to client\n",
+			  vblwait->reply.sequence);
 	} else {
-		TAILQ_INSERT_TAIL(&dev->vblank->vb_crtcs[crtc].vbl_events,
-		    &vev->base, link);
+		DPRINTF("vblank wait interrupted by signal\n");
 	}
-	mtx_leave(&dev->event_lock);
 
-	return (0);
+done:
+	drm_vblank_put(dev, crtc);
+	return ret;
 }
 
 void
 drm_handle_vblank_events(struct drm_device *dev, int crtc)
 {
-	struct drmevlist		*list;
-	struct drm_pending_event	*ev, *tmp;
-	struct drm_pending_vblank_event	*vev;
-	struct timeval			 now;
-	u_int				 seq;
+	struct drmevlist *list;
+	struct drm_pending_event *ev, *tmp;
+	struct drm_pending_vblank_event *vev;
+	struct timeval now;
+	unsigned int seq;
 
-	list = &dev->vblank->vb_crtcs[crtc].vbl_events;
-	microtime(&now);
-	seq = drm_vblank_count(dev, crtc);
+	list = &dev->vbl_events;
+	seq = drm_vblank_count_and_time(dev, crtc, &now);
 
 	mtx_enter(&dev->event_lock);
+
 	for (ev = TAILQ_FIRST(list); ev != TAILQ_END(list); ev = tmp) {
 		tmp = TAILQ_NEXT(ev, link);
 
 		vev = (struct drm_pending_vblank_event *)ev;
 
-		if ((seq - vev->event.sequence) > (1 << 23))
+		if (vev->pipe != crtc)
+			continue;
+		if ((seq - vev->event.sequence) > (1<<23))
 			continue;
-		DPRINTF("%s: got vblank event on crtc %d, value %d\n",
-		    __func__, crtc, seq);
-		
-		vev->event.sequence = seq;
-		vev->event.tv_sec = now.tv_sec;
-		vev->event.tv_usec = now.tv_usec;
-		drm_vblank_put(dev, crtc);
+
+		DPRINTF("vblank event on %d, current %d\n",
+			  vev->event.sequence, seq);
+
 		TAILQ_REMOVE(list, ev, link);
-		TAILQ_INSERT_TAIL(&ev->file_priv->evlist, ev, link);
-		wakeup(&ev->file_priv->evlist);
-		selwakeup(&ev->file_priv->rsel);
+		drm_vblank_put(dev, vev->pipe);
+		send_vblank_event(dev, vev, seq, &now);
 	}
+
 	mtx_leave(&dev->event_lock);
+
+//	trace_drm_vblank_event(crtc, seq);
 }
 
+/**
+ * drm_handle_vblank - handle a vblank event
+ * @dev: DRM device
+ * @crtc: where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ */
 bool
 drm_handle_vblank(struct drm_device *dev, int crtc)
 {
-	/*
-	 * XXX if we had proper atomic operations this mutex wouldn't
-	 * XXX need to be held.
+	u32 vblcount;
+	s64 diff_ns;
+	struct timeval tvblank;
+
+	if (!dev->num_crtcs)
+		return false;
+
+	/* Need timestamp lock to prevent concurrent execution with
+	 * vblank enable/disable, as this would cause inconsistent
+	 * or corrupted timestamps and vblank counts.
+	 */
+	mtx_enter(&dev->vblank_time_lock);
+
+	/* Vblank irq handling disabled. Nothing to do. */
+	if (!dev->vblank_enabled[crtc]) {
+		mtx_leave(&dev->vblank_time_lock);
+		return false;
+	}
+
+	/* Fetch corresponding timestamp for this vblank interval from
+	 * driver and store it in proper slot of timestamp ringbuffer.
 	 */
-	mtx_enter(&dev->vblank->vb_lock);
-	dev->vblank->vb_crtcs[crtc].vbl_count++;
-	wakeup(&dev->vblank->vb_crtcs[crtc]);
-	mtx_leave(&dev->vblank->vb_lock);
+
+	/* Get current timestamp and count. */
+	vblcount = atomic_read(&dev->_vblank_count[crtc]);
+	drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
+
+	/* Compute time difference to timestamp of last vblank */
+	diff_ns = timeval_to_ns(&tvblank) -
+		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
+
+	/* Update vblank timestamp and count if at least
+	 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
+	 * difference between last stored timestamp and current
+	 * timestamp. A smaller difference means basically
+	 * identical timestamps. Happens if this vblank has
+	 * been already processed and this is a redundant call,
+	 * e.g., due to spurious vblank interrupts. We need to
+	 * ignore those for accounting.
+	 */
+	if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
+		/* Store new timestamp in ringbuffer. */
+		vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
+
+		/* Increment cooked vblank count. This also atomically commits
+		 * the timestamp computed above.
+		 */
+//		smp_mb__before_atomic_inc();
+		atomic_inc(&dev->_vblank_count[crtc]);
+//		smp_mb__after_atomic_inc();
+	} else {
+		DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
+			  crtc, (int) diff_ns);
+	}
+
+	wakeup(&dev->vbl_queue[crtc]);
 	drm_handle_vblank_events(dev, crtc);
+
+	mtx_leave(&dev->vblank_time_lock);
 	return true;
 }