diff = (flags & DRM_CALLED_FROM_VBLIRQ) != 0;
}
+ /*
+ * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
+ * interval? If so then vblank irqs keep running and it will likely
+ * happen that the hardware vblank counter is not trustworthy as it
+ * might reset at some point in that interval and vblank timestamps
+ * are not trustworthy either in that interval. Iow. this can result
+ * in a bogus diff >> 1 which must be avoided as it would cause
+ * random large forward jumps of the software vblank counter.
+ */
+ if (diff > 1 && (vblank->inmodeset & 0x2)) {
+ DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
+ " due to pre-modeset.\n", pipe, diff);
+ 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);
/* Subtract time delta from raw timestamp to get final
* vblank_time timestamp for end of vblank.
*/
- if (delta_ns < 0)
- etime = ktime_add_ns(etime, -delta_ns);
- else
- etime = ktime_sub_ns(etime, delta_ns);
+ etime = ktime_sub_ns(etime, delta_ns);
*vblank_time = ktime_to_timeval(etime);
DRM_DEBUG_VBL("crtc %u : v 0x%x p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
struct drm_pending_vblank_event *e,
unsigned long seq, struct timeval *now)
{
- assert_spin_locked(&dev->event_lock);
-
e->event.sequence = seq;
e->event.tv_sec = now->tv_sec;
e->event.tv_usec = now->tv_usec;
- list_add_tail(&e->base.link,
- &e->base.file_priv->event_list);
- wake_up_interruptible(&e->base.file_priv->event_wait);
+ drm_send_event_locked(dev, &e->base);
+
trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
e->event.sequence);
}
spin_lock_irqsave(&dev->event_lock, irqflags);
spin_lock(&dev->vbl_lock);
- vblank_disable_and_save(dev, pipe);
+ DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
+ pipe, vblank->enabled, vblank->inmodeset);
+
+ /* Avoid redundant vblank disables without previous drm_vblank_on(). */
+ if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
+ vblank_disable_and_save(dev, pipe);
+
wake_up(&vblank->queue);
/*
return;
spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
+ pipe, vblank->enabled, vblank->inmodeset);
+
/* Drop our private "prevent drm_vblank_get" refcount */
if (vblank->inmodeset) {
atomic_dec(&vblank->refcount);
* re-enable interrupts if there are users left, or the
* user wishes vblank interrupts to be enabled all the time.
*/
- if (atomic_read(&vblank->refcount) != 0 ||
- (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
+ if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
WARN_ON(drm_vblank_enable(dev, pipe));
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
if (vblank->inmodeset) {
spin_lock_irqsave(&dev->vbl_lock, irqflags);
dev->vblank_disable_allowed = true;
+ drm_reset_vblank_timestamp(dev, pipe);
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
if (vblank->inmodeset & 0x2)
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 *)) kfree;
spin_lock_irqsave(&dev->event_lock, flags);
goto err_unlock;
}
- if (file_priv->event_space < sizeof(e->event)) {
- ret = -EBUSY;
+ ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
+ &e->event.base);
+
+ if (ret)
goto err_unlock;
- }
- file_priv->event_space -= sizeof(e->event);
seq = drm_vblank_count_and_time(dev, pipe, &now);
if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
projects / cascardo / linux.git / blobdiff