diff options
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/videobuf2-core.h | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 5287e901e17..ea55c08eddf 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -196,15 +196,24 @@ struct vb2_buffer { * before userspace accesses the buffer; optional * @buf_cleanup: called once before the buffer is freed; drivers may * perform any additional cleanup; optional - * @start_streaming: called once before entering 'streaming' state; enables - * driver to receive buffers over buf_queue() callback + * @start_streaming: called once to enter 'streaming' state; the driver may + * receive buffers with @buf_queue callback before + * @start_streaming is called; the driver gets the number + * of already queued buffers in count parameter; driver + * can return an error if hardware fails or not enough + * buffers has been queued, in such case all buffers that + * have been already given by the @buf_queue callback are + * invalidated. * @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 * @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 + * the buffer back by calling vb2_buffer_done() function; + * it is allways called after calling STREAMON ioctl; + * might be called before start_streaming callback if user + * pre-queued buffers before calling STREAMON */ struct vb2_ops { int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers, @@ -219,7 +228,7 @@ struct vb2_ops { int (*buf_finish)(struct vb2_buffer *vb); void (*buf_cleanup)(struct vb2_buffer *vb); - int (*start_streaming)(struct vb2_queue *q); + int (*start_streaming)(struct vb2_queue *q, unsigned int count); int (*stop_streaming)(struct vb2_queue *q); void (*buf_queue)(struct vb2_buffer *vb); |