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authorHans Verkuil <hverkuil@xs4all.nl>2011-03-22 10:14:07 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-03-22 16:38:16 -0300
commitb1a873a37b6551a214ad37d1eee7654a9d65fd6e (patch)
tree3667a3d36c9f7c6ae73609004331f006751c44be /Documentation/video4linux
parent2f82441a8644287e5b647329cc30b590f6fd3714 (diff)
downloadlwn-b1a873a37b6551a214ad37d1eee7654a9d65fd6e.tar.gz
lwn-b1a873a37b6551a214ad37d1eee7654a9d65fd6e.zip
[media] v4l2: use new flag to enable core priority handling
Rather than guess which driver supports core priority handling, require drivers that do to explicitly set the V4L2_FL_USE_FH_PRIO flag in video_device. Updated the core prio handling accordingly and set the flag in the three drivers that do. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r--Documentation/video4linux/v4l2-framework.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 7d09114af00b..3b15608ee070 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -577,6 +577,10 @@ You should also set these fields:
(cx8802). Since the v4l2_device cannot be associated with a particular
PCI device it is setup without a parent device. But when the struct
video_device is setup you do know which parent PCI device to use.
+- flags: optional. Set to V4L2_FL_USE_FH_PRIO if you want to let the framework
+ handle the VIDIOC_G/S_PRIORITY ioctls. This requires that you use struct
+ v4l2_fh. Eventually this flag will disappear once all drivers use the core
+ priority handling. But for now it has to be set explicitly.
If you use v4l2_ioctl_ops, then you should set .unlocked_ioctl to video_ioctl2
in your v4l2_file_operations struct.
@@ -775,7 +779,8 @@ struct v4l2_fh
struct v4l2_fh provides a way to easily keep file handle specific data
that is used by the V4L2 framework. New drivers must use struct v4l2_fh
-since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY).
+since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY)
+if the video_device flag V4L2_FL_USE_FH_PRIO is also set.
The users of v4l2_fh (in the V4L2 framework, not the driver) know
whether a driver uses v4l2_fh as its file->private_data pointer by