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V4L/DVB (11044): v4l2-device: add v4l2_device_disconnect

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Call v4l2_device_disconnect when the parent of a hotpluggable device
disconnects. This ensures that you do not have a pointer to a device that
is no longer present.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil
2009-03-14 08:28:45 -03:00
committed by Mauro Carvalho Chehab
parent 6273fda6e3
commit ae6cfaace1
4 changed files with 27 additions and 6 deletions
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11
Documentation/video4linux/v4l2-framework.txt
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@@ -105,6 +105,17 @@ You unregister with:
Unregistering will also automatically unregister all subdevs from the device.
If you have a hotpluggable device (e.g. a USB device), then when a disconnect
happens the parent device becomes invalid. Since v4l2_device has a pointer to
that parent device it has to be cleared as well to mark that the parent is
gone. To do this call:
v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
This does *not* unregister the subdevs, so you still need to call the
v4l2_device_unregister() function for that. If your driver is not hotpluggable,
then there is no need to call v4l2_device_disconnect().
Sometimes you need to iterate over all devices registered by a specific
driver. This is usually the case if multiple device drivers use the same
hardware. E.g. the ivtvfb driver is a framebuffer driver that uses the ivtv