#include <linux/vgaarb.h>
#include <linux/export.h>
-/* Access macro for slots in vblank timestamp ringbuffer. */
-#define vblanktimestamp(dev, pipe, count) \
- ((dev)->vblank[pipe].time[(count) % DRM_VBLANKTIME_RBSIZE])
-
/* Retry timestamp calculation up to 3 times to satisfy
* drm_timestamp_precision before giving up.
*/
struct timeval *t_vblank, u32 last)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
- u32 tslot;
assert_spin_locked(&dev->vblank_time_lock);
vblank->last = last;
- /* All writers hold the spinlock, but readers are serialized by
- * the latching of vblank->count below.
- */
- tslot = vblank->count + vblank_count_inc;
- vblanktimestamp(dev, pipe, tslot) = *t_vblank;
-
- /*
- * vblank timestamp updates are protected on the write side with
- * vblank_time_lock, but on the read side done locklessly using a
- * sequence-lock on the vblank counter. Ensure correct ordering using
- * memory barrriers. We need the barrier both before and also after the
- * counter update to synchronize with the next timestamp write.
- * The read-side barriers for this are in drm_vblank_count_and_time.
- */
- smp_wmb();
+ write_seqlock(&vblank->seqlock);
+ vblank->time = *t_vblank;
vblank->count += vblank_count_inc;
- smp_wmb();
+ write_sequnlock(&vblank->seqlock);
}
-/**
- * drm_reset_vblank_timestamp - reset the last timestamp to the last vblank
- * @dev: DRM device
- * @pipe: index of CRTC for which to reset the timestamp
- *
+/*
* Reset the stored timestamp for the current vblank count to correspond
* to the last vblank occurred.
*
spin_unlock(&dev->vblank_time_lock);
}
-/**
- * drm_update_vblank_count - update the master vblank counter
- * @dev: DRM device
- * @pipe: counter to update
- *
+/*
* Call back into the driver to update the appropriate vblank counter
* (specified by @pipe). Deal with wraparound, if it occurred, and
* update the last read value so we can deal with wraparound on the next
const struct timeval *t_old;
u64 diff_ns;
- t_old = &vblanktimestamp(dev, pipe, vblank->count);
+ t_old = &vblank->time;
diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
/*
diff = 1;
}
- /*
- * FIMXE: Need to replace this hack with proper seqlocks.
- *
- * Restrict the bump of the software vblank counter to a safe maximum
- * value of +1 whenever there is the possibility that concurrent readers
- * of vblank timestamps could be active at the moment, as the current
- * implementation of the timestamp caching and updating is not safe
- * against concurrent readers for calls to store_vblank() with a bump
- * of anything but +1. A bump != 1 would very likely return corrupted
- * timestamps to userspace, because the same slot in the cache could
- * be concurrently written by store_vblank() and read by one of those
- * readers without the read-retry logic detecting the collision.
- *
- * Concurrent readers can exist when we are called from the
- * drm_vblank_off() or drm_vblank_on() functions and other non-vblank-
- * irq callers. However, all those calls to us are happening with the
- * vbl_lock locked to prevent drm_vblank_get(), so the vblank refcount
- * can't increase while we are executing. Therefore a zero refcount at
- * this point is safe for arbitrary counter bumps if we are called
- * outside vblank irq, a non-zero count is not 100% safe. Unfortunately
- * we must also accept a refcount of 1, as whenever we are called from
- * drm_vblank_get() -> drm_vblank_enable() the refcount will be 1 and
- * we must let that one pass through in order to not lose vblank counts
- * during vblank irq off - which would completely defeat the whole
- * point of this routine.
- *
- * Whenever we are called from vblank irq, we have to assume concurrent
- * readers exist or can show up any time during our execution, even if
- * the refcount is currently zero, as vblank irqs are usually only
- * enabled due to the presence of readers, and because when we are called
- * from vblank irq we can't hold the vbl_lock to protect us from sudden
- * bumps in vblank refcount. Therefore also restrict bumps to +1 when
- * called from vblank irq.
- */
- if ((diff > 1) && (atomic_read(&vblank->refcount) > 1 ||
- (flags & DRM_CALLED_FROM_VBLIRQ))) {
- DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u "
- "refcount %u, vblirq %u\n", pipe, diff,
- atomic_read(&vblank->refcount),
- (flags & DRM_CALLED_FROM_VBLIRQ) != 0);
- diff = 1;
- }
-
DRM_DEBUG_VBL("updating vblank count on crtc %u:"
" current=%u, diff=%u, hw=%u hw_last=%u\n",
pipe, vblank->count, diff, cur_vblank, vblank->last);
store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
}
+/**
+ * drm_accurate_vblank_count - retrieve the master vblank counter
+ * @crtc: which counter to retrieve
+ *
+ * This function is similar to @drm_crtc_vblank_count but this
+ * function interpolates to handle a race with vblank irq's.
+ *
+ * This is mostly useful for hardware that can obtain the scanout
+ * position, but doesn't have a frame counter.
+ */
+u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
+{
+ struct drm_device *dev = crtc->dev;
+ unsigned int pipe = drm_crtc_index(crtc);
+ u32 vblank;
+ unsigned long flags;
+
+ WARN(!dev->driver->get_vblank_timestamp,
+ "This function requires support for accurate vblank timestamps.");
+
+ spin_lock_irqsave(&dev->vblank_time_lock, flags);
+
+ drm_update_vblank_count(dev, pipe, 0);
+ vblank = drm_vblank_count(dev, pipe);
+
+ spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
+
+ return vblank;
+}
+EXPORT_SYMBOL(drm_accurate_vblank_count);
+
/*
* Disable vblank irq's on crtc, make sure that last vblank count
* of hardware and corresponding consistent software vblank counter
init_waitqueue_head(&vblank->queue);
setup_timer(&vblank->disable_timer, vblank_disable_fn,
(unsigned long)vblank);
+ seqlock_init(&vblank->seqlock);
}
DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
/*
* Wake up any waiters so they don't hang. This is just to paper over
- * isssues for UMS drivers which aren't in full control of their
+ * issues for UMS drivers which aren't in full control of their
* vblank/irq handling. KMS drivers must ensure that vblanks are all
* disabled when uninstalling the irq handler.
*/
return 0;
if (drm_core_check_feature(dev, DRIVER_MODESET))
return 0;
- /* UMS was only ever support on pci devices. */
+ /* UMS was only ever supported on pci devices. */
if (WARN_ON(!dev->pdev))
return -EINVAL;
*
* This is the legacy version of drm_crtc_vblank_count_and_time().
*/
-u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
- struct timeval *vblanktime)
+static u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
+ struct timeval *vblanktime)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
- int count = DRM_TIMESTAMP_MAXRETRIES;
- u32 cur_vblank;
+ u32 vblank_count;
+ unsigned int seq;
if (WARN_ON(pipe >= dev->num_crtcs))
return 0;
- /*
- * Vblank timestamps are read lockless. To ensure consistency the vblank
- * counter is rechecked and ordering is ensured using memory barriers.
- * This works like a seqlock. The write-side barriers are in store_vblank.
- */
do {
- cur_vblank = vblank->count;
- smp_rmb();
- *vblanktime = vblanktimestamp(dev, pipe, cur_vblank);
- smp_rmb();
- } while (cur_vblank != vblank->count && --count > 0);
+ seq = read_seqbegin(&vblank->seqlock);
+ vblank_count = vblank->count;
+ *vblanktime = vblank->time;
+ } while (read_seqretry(&vblank->seqlock, seq));
- return cur_vblank;
+ return vblank_count;
}
-EXPORT_SYMBOL(drm_vblank_count_and_time);
/**
* drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
* 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 vblank counter value.
- *
- * This is the native KMS version of drm_vblank_count_and_time().
*/
u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
struct timeval *vblanktime)
e->event.tv_sec = now->tv_sec;
e->event.tv_usec = now->tv_usec;
- drm_send_event_locked(dev, &e->base);
-
trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
e->event.sequence);
-}
-
-/**
- * drm_arm_vblank_event - arm vblank event after pageflip
- * @dev: DRM device
- * @pipe: CRTC index
- * @e: the event to prepare to send
- *
- * A lot of drivers need to generate vblank events for the very next vblank
- * interrupt. For example when the page flip interrupt happens when the page
- * flip gets armed, but not when it actually executes within the next vblank
- * period. This helper function implements exactly the required vblank arming
- * behaviour.
- *
- * Caller must hold event lock. Caller must also hold a vblank reference for
- * the event @e, which will be dropped when the next vblank arrives.
- *
- * This is the legacy version of drm_crtc_arm_vblank_event().
- */
-void drm_arm_vblank_event(struct drm_device *dev, unsigned int pipe,
- struct drm_pending_vblank_event *e)
-{
- assert_spin_locked(&dev->event_lock);
- e->pipe = pipe;
- e->event.sequence = drm_vblank_count(dev, pipe);
- list_add_tail(&e->base.link, &dev->vblank_event_list);
+ drm_send_event_locked(dev, &e->base);
}
-EXPORT_SYMBOL(drm_arm_vblank_event);
/**
* drm_crtc_arm_vblank_event - arm vblank event after pageflip
*
* Caller must hold event lock. Caller must also hold a vblank reference for
* the event @e, which will be dropped when the next vblank arrives.
- *
- * This is the native KMS version of drm_arm_vblank_event().
*/
void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
struct drm_pending_vblank_event *e)
{
- drm_arm_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
+ struct drm_device *dev = crtc->dev;
+ unsigned int pipe = drm_crtc_index(crtc);
+
+ assert_spin_locked(&dev->event_lock);
+
+ e->pipe = pipe;
+ e->event.sequence = drm_vblank_count(dev, pipe);
+ list_add_tail(&e->base.link, &dev->vblank_event_list);
}
EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
/**
- * drm_send_vblank_event - helper to send vblank event after pageflip
- * @dev: DRM device
- * @pipe: CRTC index
+ * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
+ * @crtc: the source CRTC of the vblank event
* @e: the event to send
*
* Updates sequence # and timestamp on event, and sends it to userspace.
* Caller must hold event lock.
- *
- * This is the legacy version of drm_crtc_send_vblank_event().
*/
-void drm_send_vblank_event(struct drm_device *dev, unsigned int pipe,
- struct drm_pending_vblank_event *e)
+void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+ struct drm_pending_vblank_event *e)
{
+ struct drm_device *dev = crtc->dev;
+ unsigned int seq, pipe = drm_crtc_index(crtc);
struct timeval now;
- unsigned int seq;
if (dev->num_crtcs > 0) {
seq = drm_vblank_count_and_time(dev, pipe, &now);
e->pipe = pipe;
send_vblank_event(dev, e, seq, &now);
}
-EXPORT_SYMBOL(drm_send_vblank_event);
-
-/**
- * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
- * @crtc: the source CRTC of the vblank event
- * @e: the event to send
- *
- * Updates sequence # and timestamp on event, and sends it to userspace.
- * Caller must hold event lock.
- *
- * This is the native KMS version of drm_send_vblank_event().
- */
-void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
- struct drm_pending_vblank_event *e)
-{
- drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
-}
EXPORT_SYMBOL(drm_crtc_send_vblank_event);
/**
* Returns:
* Zero on success or a negative error code on failure.
*/
-int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
+static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
unsigned long irqflags;
return ret;
}
-EXPORT_SYMBOL(drm_vblank_get);
/**
* drm_crtc_vblank_get - get a reference count on vblank events
* Acquire a reference count on vblank events to avoid having them disabled
* while in use.
*
- * This is the native kms version of drm_vblank_get().
- *
* Returns:
* Zero on success or a negative error code on failure.
*/
*
* This is the legacy version of drm_crtc_vblank_put().
*/
-void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
+static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
jiffies + ((drm_vblank_offdelay * HZ)/1000));
}
}
-EXPORT_SYMBOL(drm_vblank_put);
/**
* drm_crtc_vblank_put - give up ownership of vblank events
*
* Release ownership of a given vblank counter, turning off interrupts
* if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
- *
- * This is the native kms version of drm_vblank_put().
*/
void drm_crtc_vblank_put(struct drm_crtc *crtc)
{
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;
- }
-
DRM_DEBUG("event on vblank count %d, current %d, crtc %u\n",
vblwait->request.sequence, seq, pipe);
goto done;
}
+ if ((flags & _DRM_VBLANK_NEXTONMISS) &&
+ (seq - vblwait->request.sequence) <= (1 << 23)) {
+ vblwait->request.sequence = seq + 1;
+ }
+
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, pipe, vblwait, file_priv);
}
- if ((flags & _DRM_VBLANK_NEXTONMISS) &&
- (seq - vblwait->request.sequence) <= (1<<23)) {
- vblwait->request.sequence = seq + 1;
- }
-
DRM_DEBUG("waiting on vblank count %d, crtc %u\n",
vblwait->request.sequence, pipe);
- vblank->last_wait = vblwait->request.sequence;
DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
(((drm_vblank_count(dev, pipe) -
vblwait->request.sequence) <= (1 << 23)) ||
projects / cascardo / linux.git / blobdiff