Commit cecfe9b8 authored Sep 25, 2017 by Hans Verkuil Committed by Mauro Carvalho Chehab Oct 04, 2017

[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>

parent 5b2c8da1

drivers/media/v4l2-core/v4l2-ctrls.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -2818,7 +2818,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
	static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)		static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
	{		{
	if (which == 0 \|\| which == V4L2_CTRL_WHICH_DEF_VAL)		if (which == 0 \|\| which == V4L2_CTRL_WHICH_DEF_VAL)
	return list_empty(&hdl->ctrl_refs) ? -EINVAL : 0;		return 0;
	return find_ref_lock(hdl, which \| 1) ? 0 : -EINVAL;		return find_ref_lock(hdl, which \| 1) ? 0 : -EINVAL;
	}		}