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Commit f61bf13b authored by Kamil Debski's avatar Kamil Debski Committed by Mauro Carvalho Chehab
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[media] vb2: add allow_zero_bytesused flag to the vb2_queue struct 



The vb2: fix bytesused == 0 handling (8a75ffb8) patch changed the behavior
of __fill_vb2_buffer function, so that if bytesused is 0 it is set to the
size of the buffer. However, bytesused set to 0 is used by older codec
drivers as as indication used to mark the end of stream.

To keep backward compatibility, this patch adds a flag passed to the
vb2_queue_init function - allow_zero_bytesused. If the flag is set upon
initialization of the queue, the videobuf2 keeps the value of bytesused
intact in the OUTPUT queue and passes it to the driver.

Reported-by: default avatarNicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: default avatarKamil Debski <k.debski@samsung.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 06e7a9b6

drivers/media/v4l2-core/videobuf2-core.c

+33 −6
Original line number Diff line number Diff line
@@ -1247,6 +1247,16 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b 
{

	unsigned int plane;



	if (V4L2_TYPE_IS_OUTPUT(b->type)) {

		if (WARN_ON_ONCE(b->bytesused == 0)) {

			pr_warn_once("use of bytesused == 0 is deprecated and will be removed in the future,\n");

			if (vb->vb2_queue->allow_zero_bytesused)

				pr_warn_once("use VIDIOC_DECODER_CMD(V4L2_DEC_CMD_STOP) instead.\n");

			else

				pr_warn_once("use the actual size instead.\n");

		}

	}



	if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {

		if (b->memory == V4L2_MEMORY_USERPTR) {

			for (plane = 0; plane < vb->num_planes; ++plane) {
@@ -1276,11 +1286,20 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b 
			 * userspace clearly never bothered to set it and

			 * it's a safe assumption that they really meant to

			 * use the full plane sizes.

			 *

			 * Some drivers, e.g. old codec drivers, use bytesused == 0

			 * as a way to indicate that streaming is finished.

			 * In that case, the driver should use the

			 * allow_zero_bytesused flag to keep old userspace

			 * applications working.

			 */

			for (plane = 0; plane < vb->num_planes; ++plane) {

				struct v4l2_plane *pdst = &v4l2_planes[plane];

				struct v4l2_plane *psrc = &b->m.planes[plane];



				if (vb->vb2_queue->allow_zero_bytesused)

					pdst->bytesused = psrc->bytesused;

				else

					pdst->bytesused = psrc->bytesused ?

						psrc->bytesused : pdst->length;

				pdst->data_offset = psrc->data_offset;
@@ -1295,6 +1314,11 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b 
		 *

		 * If bytesused == 0 for the output buffer, then fall back

		 * to the full buffer size as that's a sensible default.

		 *

		 * Some drivers, e.g. old codec drivers, use bytesused == 0 as

		 * a way to indicate that streaming is finished. In that case,

		 * the driver should use the allow_zero_bytesused flag to keep

		 * old userspace applications working.

		 */

		if (b->memory == V4L2_MEMORY_USERPTR) {

			v4l2_planes[0].m.userptr = b->m.userptr;
@@ -1306,10 +1330,13 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b 
			v4l2_planes[0].length = b->length;

		}



		if (V4L2_TYPE_IS_OUTPUT(b->type))

		if (V4L2_TYPE_IS_OUTPUT(b->type)) {

			if (vb->vb2_queue->allow_zero_bytesused)

				v4l2_planes[0].bytesused = b->bytesused;

			else

				v4l2_planes[0].bytesused = b->bytesused ?

					b->bytesused : v4l2_planes[0].length;

		else

		} else

			v4l2_planes[0].bytesused = 0;



	}

include/media/videobuf2-core.h

+2 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ struct v4l2_fh; 
 * @io_modes:	supported io methods (see vb2_io_modes enum)

 * @fileio_read_once:		report EOF after reading the first buffer

 * @fileio_write_immediately:	queue buffer after each write() call

 * @allow_zero_bytesused:	allow bytesused == 0 to be passed to the driver

 * @lock:	pointer to a mutex that protects the vb2_queue struct. The

 *		driver can set this to a mutex to let the v4l2 core serialize

 *		the queuing ioctls. If the driver wants to handle locking
@@ -388,6 +389,7 @@ struct vb2_queue { 
	unsigned int			io_modes;

	unsigned			fileio_read_once:1;

	unsigned			fileio_write_immediately:1;

	unsigned			allow_zero_bytesused:1;



	struct mutex			*lock;

	struct v4l2_fh			*owner;