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authorLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>2013-08-02 04:44:38 +0400
committerMauro Carvalho Chehab <m.chehab@samsung.com>2013-08-18 14:20:59 +0400
commit5548a382508f1f76320e1ed55524dda73234299d (patch)
tree61e6617bb9e72adb1c0b2dba6f0993b44d7e0df2 /include/media
parentc09aada7ac8a8c03970bd2fb41176647da7cef99 (diff)
downloadlinux-5548a382508f1f76320e1ed55524dda73234299d.tar.xz
[media] media: vb2: Clarify queue_setup() and buf_prepare() usage documentation
Explain how the two operations must handle formats and validate buffer sizes when used with VIDIOC_CREATE_BUFS. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Diffstat (limited to 'include/media')
-rw-r--r--include/media/videobuf2-core.h11
1 files changed, 7 insertions, 4 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index d88a098d1aff..6781258d0b67 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -219,8 +219,9 @@ struct vb2_buffer {
* configured format and *num_buffers is the total number
* of buffers, that are being allocated. When called from
* VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
- * target frame format. In this case *num_buffers are being
- * allocated additionally to q->num_buffers.
+ * target frame format (if the format isn't valid the
+ * callback must return -EINVAL). In this case *num_buffers
+ * are being allocated additionally to q->num_buffers.
* @wait_prepare: release any locks taken while calling vb2 functions;
* it is called before an ioctl needs to wait for a new
* buffer to arrive; required to avoid a deadlock in
@@ -236,8 +237,10 @@ struct vb2_buffer {
* @buf_prepare: called every time the buffer is queued from userspace
* and from the VIDIOC_PREPARE_BUF ioctl; drivers may
* perform any initialization required before each hardware
- * operation in this callback; if an error is returned, the
- * buffer will not be queued in driver; optional
+ * operation in this callback; drivers that support
+ * VIDIOC_CREATE_BUFS must also validate the buffer size;
+ * if an error is returned, the buffer will not be queued
+ * in driver; optional
* @buf_finish: called before every dequeue of the buffer back to
* userspace; drivers may perform any operations required
* before userspace accesses the buffer; optional