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--;
}
}
mtx_leave(&vbl->vb_lock);
return (ret);
}
/**
* 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)
{
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(&dev->vbl_lock);
return ret;
}
