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Commit 68a06bd0 authored by Luca Ceresoli's avatar Luca Ceresoli Committed by Mauro Carvalho Chehab
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media: vb2-core: document the REQUEUEING state 



VB2_BUF_STATE_REQUEUEING is accepted by vb2_buffer_done() but not
documented, so add it along with notes about calls in interrupt
context.

Signed-off-by: default avatarLuca Ceresoli <luca@lucaceresoli.net>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 45ad3999

include/media/videobuf2-core.h

+15 −9
Original line number Diff line number Diff line
@@ -358,12 +358,12 @@ 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
@@ -601,8 +601,9 @@ 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.

 *		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
@@ -613,7 +614,12 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); 
 * While streaming a buffer can only be returned in state DONE or ERROR.

 * 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 to put them back into the queue.

 * 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);