tree 9df12370ca6fa60d7ebc53111a11829f44e95a24
parent 5b2c8da1b040c4608c7cfdc0dd96bcaa190af268
author Hans Verkuil <hverkuil@xs4all.nl> 1506332462 -0300
committer Mauro Carvalho Chehab <mchehab@osg.samsung.com> 1507147500 -0300

[media] v4l2-ctrls.c: allow empty control handlers

If you have a control handler that does not contain any controls, then
currently calling VIDIOC_G/S/TRY_EXT_CTRLS with count == 0 will return
-EINVAL in the class_check() function.

This is not correct, there is no reason why this should return an error.

The purpose of setting count to 0 is to test if the ioctl can mix controls
from different control classes. And this is possible. The fact that there
are not actually any controls defined is another matter that is unrelated
to this test.

This caused v4l2-compliance to fail, so that is fixed with this patch applied.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Tested-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>