aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorHans Verkuil <hverkuil@xs4all.nl>2011-03-22 09:14:07 -0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-03-22 15:38:16 -0400
commitb1a873a37b6551a214ad37d1eee7654a9d65fd6e (patch)
tree3667a3d36c9f7c6ae73609004331f006751c44be /Documentation
parent2f82441a8644287e5b647329cc30b590f6fd3714 (diff)
[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')
-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:
577 (cx8802). Since the v4l2_device cannot be associated with a particular 577 (cx8802). Since the v4l2_device cannot be associated with a particular
578 PCI device it is setup without a parent device. But when the struct 578 PCI device it is setup without a parent device. But when the struct
579 video_device is setup you do know which parent PCI device to use. 579 video_device is setup you do know which parent PCI device to use.
580- flags: optional. Set to V4L2_FL_USE_FH_PRIO if you want to let the framework
581 handle the VIDIOC_G/S_PRIORITY ioctls. This requires that you use struct
582 v4l2_fh. Eventually this flag will disappear once all drivers use the core
583 priority handling. But for now it has to be set explicitly.
580 584
581If you use v4l2_ioctl_ops, then you should set .unlocked_ioctl to video_ioctl2 585If you use v4l2_ioctl_ops, then you should set .unlocked_ioctl to video_ioctl2
582in your v4l2_file_operations struct. 586in your v4l2_file_operations struct.
@@ -775,7 +779,8 @@ struct v4l2_fh
775 779
776struct v4l2_fh provides a way to easily keep file handle specific data 780struct v4l2_fh provides a way to easily keep file handle specific data
777that is used by the V4L2 framework. New drivers must use struct v4l2_fh 781that is used by the V4L2 framework. New drivers must use struct v4l2_fh
778since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY). 782since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY)
783if the video_device flag V4L2_FL_USE_FH_PRIO is also set.
779 784
780The users of v4l2_fh (in the V4L2 framework, not the driver) know 785The users of v4l2_fh (in the V4L2 framework, not the driver) know
781whether a driver uses v4l2_fh as its file->private_data pointer by 786whether a driver uses v4l2_fh as its file->private_data pointer by