From f5360bdc5539ccd7644df7acf27e8c740ba8cf6e Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 15 Jan 2009 06:09:05 -0300 Subject: [PATCH] V4L/DVB (10252): v4l2 doc: explain why v4l2_device_unregister_subdev() has to be called. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index ff124374e9ba..cc350624237d 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -340,6 +340,12 @@ Make sure to call v4l2_device_unregister_subdev(sd) when the remove() callback is called. This will unregister the sub-device from the bridge driver. It is safe to call this even if the sub-device was never registered. +You need to do this because when the bridge driver destroys the i2c adapter +the remove() callbacks are called of the i2c devices on that adapter. +After that the corresponding v4l2_subdev structures are invalid, so they +have to be unregistered first. Calling v4l2_device_unregister_subdev(sd) +from the remove() callback ensures that this is always done correctly. + The bridge driver also has some helper functions it can use: -- 2.20.1