From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
The application should really always fill in bytesused for output
buffers, unfortunately the vb2 framework never checked for that.
So for single planar formats replace a bytesused of 0 by the length
of the buffer, and for multiplanar format do the same if bytesused is
0 for ALL planes.
This seems to be what the user really intended if v4l2_buffer was
just memset to 0.
I'm afraid that just checking for this and returning an error would
break too many applications. Quite a few drivers never check for bytesused
at all and just use the buffer length instead.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
drivers/media/v4l2-core/videobuf2-core.c | 32 +++++++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 1a09442..83e78e9 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1145,19 +1145,35 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
memset(v4l2_planes[plane].reserved, 0,
sizeof(v4l2_planes[plane].reserved));
v4l2_planes[plane].data_offset = 0;
+ v4l2_planes[plane].bytesused = 0;
}
/* Fill in driver-provided information for OUTPUT types */
if (V4L2_TYPE_IS_OUTPUT(b->type)) {
+ bool bytesused_is_used;
+
+ /* Check if bytesused == 0 for all planes */
+ for (plane = 0; plane < vb->num_planes; ++plane)
+ if (b->m.planes[plane].bytesused)
+ break;
+ bytesused_is_used = plane < vb->num_planes;
+
/*
* Will have to go up to b->length when API starts
* accepting variable number of planes.
+ *
+ * If bytesused_is_used is false, then fall back to the
+ * full buffer size. In that case userspace clearly
+ * never bothered to set it and it's a safe assumption
+ * that they really meant to use the full plane sizes.
*/
for (plane = 0; plane < vb->num_planes; ++plane) {
- v4l2_planes[plane].bytesused =
- b->m.planes[plane].bytesused;
- v4l2_planes[plane].data_offset =
- b->m.planes[plane].data_offset;
+ struct v4l2_plane *pdst = &v4l2_planes[plane];
+ struct v4l2_plane *psrc = &b->m.planes[plane];
+
+ pdst->bytesused = bytesused_is_used ?
+ psrc->bytesused : psrc->length;
+ pdst->data_offset = psrc->data_offset;
}
}
@@ -1183,9 +1199,15 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
* so fill in relevant v4l2_buffer struct fields instead.
* In videobuf we use our internal V4l2_planes struct for
* single-planar buffers as well, for simplicity.
+ *
+ * If bytesused == 0, then fall back to the full buffer size
+ * as that's a sensible default.
*/
if (V4L2_TYPE_IS_OUTPUT(b->type))
- v4l2_planes[0].bytesused = b->bytesused;
+ v4l2_planes[0].bytesused =
+ b->bytesused ? b->bytesused : b->length;
+ else
+ v4l2_planes[0].bytesused = 0;
/* Single-planar buffers never use data_offset */
v4l2_planes[0].data_offset = 0;
--
1.9.0
--
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