---

yaml
---
r: 242126
b: refs/heads/master
c: 2335e2b
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bedf8bcf6b4f90a6e31add3721a2e71877289381
+refs/heads/master: 2335e2b817186cf79a07311f14560ef8b30f6a9a

trunk/Documentation/video4linux/v4l2-framework.txt

@@ -181,6 +181,21 @@ static int __devinit drv_probe(struct pci_dev *pdev,
 	state->instance = atomic_inc_return(&drv_instance) - 1;
 }
 
+If you have multiple device nodes then it can be difficult to know when it is
+safe to unregister v4l2_device. For this purpose v4l2_device has refcounting
+support. The refcount is increased whenever video_register_device is called and
+it is decreased whenever that device node is released. When the refcount reaches
+zero, then the v4l2_device release() callback is called. You can do your final
+cleanup there.
+
+If other device nodes (e.g. ALSA) are created, then you can increase and
+decrease the refcount manually as well by calling:
+
+void v4l2_device_get(struct v4l2_device *v4l2_dev);
+
+or:
+
+int v4l2_device_put(struct v4l2_device *v4l2_dev);
 
 struct v4l2_subdev
 ------------------