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);
void drm_calc_timestamping_constants(struct drm_crtc *crtc,
const struct drm_display_mode *mode)
{
- struct drm_vblank_crtc *vblank = &crtc->dev->vblank[drm_crtc_index(crtc)];
+ struct drm_device *dev = crtc->dev;
+ unsigned int pipe = drm_crtc_index(crtc);
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
int linedur_ns = 0, framedur_ns = 0;
int dotclock = mode->crtc_clock;
+ if (!dev->num_crtcs)
+ return;
+
+ if (WARN_ON(pipe >= dev->num_crtcs))
+ return;
+
/* Valid dotclock? */
if (dotclock > 0) {
int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
struct drm_pending_vblank_event *e,
unsigned long seq, struct timeval *now)
{
- WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
+ assert_spin_locked(&dev->event_lock);
+
e->event.sequence = seq;
e->event.tv_sec = now->tv_sec;
e->event.tv_usec = now->tv_usec;
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);
+}
+EXPORT_SYMBOL(drm_arm_vblank_event);
+
+/**
+ * drm_crtc_arm_vblank_event - arm vblank event after pageflip
+ * @crtc: the source CRTC of the vblank event
+ * @e: the event 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 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);
+}
+EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
+
/**
* drm_send_vblank_event - helper to send vblank event after pageflip
* @dev: DRM device
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)
projects / firefly-linux-kernel-4.4.55.git / blobdiff