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| author |   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> | 2021-04-12 13:02:09 +0200 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2021-06-08 12:04:08 +0200 |
| commit | a810ed0b3370e0b3f448233d526d085effd1f829 (patch) | |
| tree | 2a78bd9d06cc2ba2a6e7186c2574e8aff5a4b02e /include/media | |
| parent | media: pci: tw5864: avoid usage of some characters (diff) | |
| download | linux-dev-a810ed0b3370e0b3f448233d526d085effd1f829.tar.xz linux-dev-a810ed0b3370e0b3f448233d526d085effd1f829.zip | |
media: videobuf2-v4l2.c: add vb2_queue_change_type() helper
On some platforms a video device can capture either video data or
metadata. The driver can implement vidioc functions for both video and
metadata, and use a single vb2_queue for the buffers. However, vb2_queue
requires choosing a single buffer type, which conflicts with the idea of
capturing either video or metadata.
The buffer type of vb2_queue can be changed, but it's not obvious how
this should be done in the drivers. To help this, add a new helper
function vb2_queue_change_type() which ensures the correct checks and
documents how it can be used.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/videobuf2-v4l2.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h index c203047eb834..b66585e304e2 100644 --- a/include/media/videobuf2-v4l2.h +++ b/include/media/videobuf2-v4l2.h @@ -262,6 +262,22 @@ int __must_check vb2_queue_init_name(struct vb2_queue *q, const char *name); void vb2_queue_release(struct vb2_queue *q); /** + * vb2_queue_change_type() - change the type of an inactive vb2_queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @type: the type to change to (V4L2_BUF_TYPE_VIDEO_*) + * + * This function changes the type of the vb2_queue. This is only possible + * if the queue is not busy (i.e. no buffers have been allocated). + * + * vb2_queue_change_type() can be used to support multiple buffer types using + * the same queue. The driver can implement v4l2_ioctl_ops.vidioc_reqbufs and + * v4l2_ioctl_ops.vidioc_create_bufs functions and call vb2_queue_change_type() + * before calling vb2_ioctl_reqbufs() or vb2_ioctl_create_bufs(), and thus + * "lock" the buffer type until the buffers have been released. + */ +int vb2_queue_change_type(struct vb2_queue *q, unsigned int type); + +/** * vb2_poll() - implements poll userspace operation * @q: pointer to &struct vb2_queue with videobuf2 queue. * @file: file argument passed to the poll file operation handler |