diff options
Diffstat (limited to 'include/media/videobuf2-core.h')
| -rw-r--r-- | include/media/videobuf2-core.h | 33 |
1 files changed, 20 insertions, 13 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 5b6c541e4e1b..f6818f732f34 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -296,6 +296,9 @@ struct vb2_buffer { /** * struct vb2_ops - driver-specific callbacks. * + * These operations are not called from interrupt context except where + * mentioned specifically. + * * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS() * handlers before memory allocation. It can be called * twice: if the original number of requested buffers @@ -358,12 +361,12 @@ struct vb2_buffer { * driver can return an error if hardware fails, in that * case all buffers that have been already given by * the @buf_queue callback are to be returned by the driver - * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED. - * If you need a minimum number of buffers before you can - * start streaming, then set - * &vb2_queue->min_buffers_needed. If that is non-zero then - * @start_streaming won't be called until at least that - * many buffers have been queued up by userspace. + * by calling vb2_buffer_done() with %VB2_BUF_STATE_QUEUED + * or %VB2_BUF_STATE_REQUEUEING. If you need a minimum + * number of buffers before you can start streaming, then + * set &vb2_queue->min_buffers_needed. 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 @@ -601,10 +604,9 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); * @state: state of the buffer, as defined by &enum vb2_buffer_state. * Either %VB2_BUF_STATE_DONE if the operation finished * successfully, %VB2_BUF_STATE_ERROR if the operation finished - * with an error or %VB2_BUF_STATE_QUEUED if the driver wants to - * requeue buffers. If start_streaming fails then it should return - * buffers with state %VB2_BUF_STATE_QUEUED to put them back into - * the queue. + * with an error or any of %VB2_BUF_STATE_QUEUED or + * %VB2_BUF_STATE_REQUEUEING if the driver wants to + * requeue buffers (see below). * * This function should be called by the driver after a hardware operation on * a buffer is finished and the buffer may be returned to userspace. The driver @@ -613,9 +615,14 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); * to the driver by &vb2_ops->buf_queue can be passed to this function. * * While streaming a buffer can only be returned in state DONE or ERROR. - * The start_streaming op can also return them in case the DMA engine cannot - * be started for some reason. In that case the buffers should be returned with - * state QUEUED. + * The &vb2_ops->start_streaming op can also return them in case the DMA engine + * cannot be started for some reason. In that case the buffers should be + * returned with state QUEUED or REQUEUEING to put them back into the queue. + * + * %VB2_BUF_STATE_REQUEUEING is like %VB2_BUF_STATE_QUEUED, but it also calls + * &vb2_ops->buf_queue to queue buffers back to the driver. Note that calling + * vb2_buffer_done(..., VB2_BUF_STATE_REQUEUEING) from interrupt context will + * result in &vb2_ops->buf_queue being called in interrupt context as well. */ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); |