path: root/include/media/videobuf2-core.h
diff options
authorHans Verkuil <hverkuil@xs4all.nl>2014-07-23 03:17:06 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2014-07-25 19:19:35 -0300
commitccf58cb4eac050ebe777cfcb209bc53d58f5fd79 (patch)
tree385a7bc450993342ccfb74d017c300575f87bb7a /include/media/videobuf2-core.h
parent5d0360a4f027576e5419d4a7c711c9ca0f1be8ca (diff)
[media] vb2: fix videobuf2-core.h comments
A lot of work was done in vb2 to regulate how drivers and the vb2 core handle buffer ownership, but inexplicably the videobuf2-core.h comments were never updated. Do so now. The same was true for the replacement of the -ENOBUFS mechanism by the min_buffers_needed field. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Diffstat (limited to 'include/media/videobuf2-core.h')
1 files changed, 10 insertions, 6 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 1a262aeb1741..fc910a622451 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -294,15 +294,19 @@ struct vb2_buffer {
* of already queued buffers in count parameter; driver
* can return an error if hardware fails, in that case all
* buffers that have been already given by the @buf_queue
- * callback are invalidated.
- * If there were not enough queued buffers to start
- * streaming, then this callback returns -ENOBUFS, and the
- * vb2 core will retry calling @start_streaming when a new
- * buffer is queued.
+ * callback are to be returned by the driver by calling
+ * @vb2_buffer_done(VB2_BUF_STATE_DEQUEUED).
+ * If you need a minimum number of buffers before you can
+ * start streaming, then set @min_buffers_needed in the
+ * vb2_queue structure. If that is non-zero then
+ * start_streaming won't be called until at least that
+ * many buffers have been queued up by userspace.
* @stop_streaming: called when 'streaming' state must be disabled; driver
* should stop any DMA transactions or wait until they
* finish and give back all buffers it got from buf_queue()
- * callback; may use vb2_wait_for_all_buffers() function
+ * callback by calling @vb2_buffer_done() with either
+ * vb2_wait_for_all_buffers() function
* @buf_queue: passes buffer vb to the driver; driver may start
* hardware operation on this buffer; driver should give
* the buffer back by calling vb2_buffer_done() function;

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