From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
The data_offset field tells the start of the image data from the beginning
of the buffer. The bsize field in struct v4l2_buffer includes this, but the
sizeimage field in struct v4l2_pix_format does not.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
Documentation/DocBook/media/v4l/compat.xml | 11 +++++++++++
Documentation/DocBook/media/v4l/io.xml | 18 +++++++++++++++---
Documentation/DocBook/media/v4l/vidioc-qbuf.xml | 3 +--
drivers/media/usb/cpia2/cpia2_v4l.c | 2 +-
drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 4 ++--
drivers/media/v4l2-core/videobuf2-core.c | 17 ++++++++++++-----
include/uapi/linux/videodev2.h | 4 +++-
7 files changed, 45 insertions(+), 14 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml
index 0a2debf..ad54e72 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2579,6 +2579,17 @@ fields changed from _s32 to _u32.
</orderedlist>
</section>
+ <section>
+ <title>V4L2 in Linux 3.20</title>
+ <orderedlist>
+ <listitem>
+ <para>Replaced <structfield>reserved2</structfield> by
+ <strucfield>data_offset<structfield> in struct
+ <structname>v4l2_buffer</structname>.</para>
+ </listitem>
+ </orderedlist>
+ </section>
+
<section id="other">
<title>Relation of V4L2 to other Linux multimedia APIs</title>
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index 1c17f80..13baeac 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -839,10 +839,22 @@ is the file descriptor associated with a DMABUF buffer.</entry>
</row>
<row>
<entry>__u32</entry>
- <entry><structfield>reserved2</structfield></entry>
+ <entry><structfield>data_offset</structfield></entry>
<entry></entry>
- <entry>A place holder for future extensions. Applications
-should set this to 0.</entry>
+ <entry>
+ Start of the image data from the beginning of the buffer in
+ bytes. Applications must set this for both
+ <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> buffers
+ whereas driver must set this for
+ <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> buffers
+ before &VIDIOC-PREPARE-BUF; and &VIDIOC-QBUF; IOCTLs. Note
+ that data_offset is included in
+ <structfield>bytesused</structfield>. So the size of the image
+ in the plane is <structfield>bytesused</structfield>-
+ <structfield>data_offset</structfield> at offset
+ <structfield>data_offset</structfield> from the start of the
+ plane.
+ </entry>
</row>
<row>
<entry>__u32</entry>
diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
index 3504a7f..f529e4d 100644
--- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
@@ -72,8 +72,7 @@ initialize the <structfield>bytesused</structfield>,
<structfield>timestamp</structfield> fields, see <xref
linkend="buffer" /> for details.
Applications must also set <structfield>flags</structfield> to 0.
-The <structfield>reserved2</structfield> and
-<structfield>reserved</structfield> fields must be set to 0. When using
+The <structfield>reserved</structfield> field must be set to 0. When using
the <link linkend="planar-apis">multi-planar API</link>, the
<structfield>m.planes</structfield> field must contain a userspace pointer
to a filled-in array of &v4l2-plane; and the <structfield>length</structfield>
diff --git a/drivers/media/usb/cpia2/cpia2_v4l.c b/drivers/media/usb/cpia2/cpia2_v4l.c
index 9caea83..a94e83a 100644
--- a/drivers/media/usb/cpia2/cpia2_v4l.c
+++ b/drivers/media/usb/cpia2/cpia2_v4l.c
@@ -952,7 +952,7 @@ static int cpia2_dqbuf(struct file *file, void *fh, struct v4l2_buffer *buf)
buf->sequence = cam->buffers[buf->index].seq;
buf->m.offset = cam->buffers[buf->index].data - cam->frame_buffer;
buf->length = cam->frame_size;
- buf->reserved2 = 0;
+ buf->data_offset = 0;
buf->reserved = 0;
memset(&buf->timecode, 0, sizeof(buf->timecode));
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index af63543..e238066 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -326,7 +326,7 @@ struct v4l2_buffer32 {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ __u32 data_offset;
__u32 reserved;
};
@@ -491,7 +491,7 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
copy_to_user(&up->timecode, &kp->timecode, sizeof(struct v4l2_timecode)) ||
put_user(kp->sequence, &up->sequence) ||
- put_user(kp->reserved2, &up->reserved2) ||
+ put_user(kp->data_offset, &up->data_offset) ||
put_user(kp->reserved, &up->reserved))
return -EFAULT;
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 7aed8f2..3162de8 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -607,6 +607,9 @@ static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
if (b->bytesused > length)
return -EINVAL;
+
+ if (b->data_offset > 0 && b->data_offset >= bytesused)
+ return -EINVAL;
}
return 0;
@@ -657,7 +660,6 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
/* Copy back data such as timestamp, flags, etc. */
memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m));
- b->reserved2 = vb->v4l2_buf.reserved2;
b->reserved = vb->v4l2_buf.reserved;
if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) {
@@ -666,14 +668,17 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
* for it. The caller has already verified memory and size.
*/
b->length = vb->num_planes;
+ b->data_offset = vb->v4l2_buf.data_offset;
memcpy(b->m.planes, vb->v4l2_planes,
b->length * sizeof(struct v4l2_plane));
} else {
/*
- * We use length and offset in v4l2_planes array even for
- * single-planar buffers, but userspace does not.
+ * We use length, data_offset and bytesused in
+ * v4l2_planes array even for single-planar buffers,
+ * but userspace does not.
*/
b->length = vb->v4l2_planes[0].length;
+ b->data_offset = vb->v4l2_planes[0].data_offset;
b->bytesused = vb->v4l2_planes[0].bytesused;
if (q->memory == V4L2_MEMORY_MMAP)
b->m.offset = vb->v4l2_planes[0].m.mem_offset;
@@ -1306,11 +1311,13 @@ 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)) {
v4l2_planes[0].bytesused = b->bytesused ?
b->bytesused : v4l2_planes[0].length;
- else
+ v4l2_planes[0].data_offset = b->data_offset;
+ } else {
v4l2_planes[0].bytesused = 0;
+ }
}
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 1c2f84f..e9806c6 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -675,6 +675,8 @@ struct v4l2_plane {
* @length: size in bytes of the buffer (NOT its payload) for single-plane
* buffers (when type != *_MPLANE); number of elements in the
* planes array for multi-plane buffers
+ * @data_offset: Offset of the start of data from the beginning of the
+ * buffer. Typically zero.
*
* Contains data exchanged by application and driver using one of the Streaming
* I/O methods.
@@ -698,7 +700,7 @@ struct v4l2_buffer {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ __u32 data_offset;
__u32 reserved;
};
--
1.9.1
--
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