| Message ID | 1424360450-13048-2-git-send-email-k.debski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/19/2015 04:40 PM, Kamil Debski wrote: > The vb2: fix bytesused == 0 handling (8a75ffb) 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: Nicolas Dufresne <nicolas.dufresne@collabora.com> > Signed-off-by: Kamil Debski <k.debski@samsung.com> > --- > drivers/media/v4l2-core/videobuf2-core.c | 29 +++++++++++++++++++++++------ > include/media/videobuf2-core.h | 2 ++ > 2 files changed, 25 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c > index 5cd60bf..b8a30d5 100644 > --- a/drivers/media/v4l2-core/videobuf2-core.c > +++ b/drivers/media/v4l2-core/videobuf2-core.c > @@ -1276,13 +1276,22 @@ 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]; > > - pdst->bytesused = psrc->bytesused ? > - psrc->bytesused : pdst->length; > + 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 +1304,11 @@ 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 +1320,13 @@ 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)) > - v4l2_planes[0].bytesused = b->bytesused ? > - b->bytesused : v4l2_planes[0].length; > - else > + if (V4L2_TYPE_IS_OUTPUT(b->type)) { > + if (vb->vb2_queue->allow_zero_bytesused) > + v4l2_planes[0].bytesused = b->bytesused; I would really prefer to see a pr_warn_once here telling end-users that this is deprecated, replaced by DEC_CMD_STOP and that it will be removed in 201X. Actually, I think something like this will work well: if (WARN_ON_ONCE(b->bytesused == 0)) { pr_warn_once("use of bytesused == 0 is deprecated and will be removed in 2017,\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"); } I believe both the coda and s5p-mfc drivers support V4L2_DEC_CMD_STOP as a working alternative to this? Regards, Hans > + else > + v4l2_planes[0].bytesused = b->bytesused ? > + b->bytesused : v4l2_planes[0].length; > + } else > v4l2_planes[0].bytesused = 0; > > } > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > index e49dc6b..a5790fd 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -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; > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 5cd60bf..b8a30d5 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1276,13 +1276,22 @@ 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]; - pdst->bytesused = psrc->bytesused ? - psrc->bytesused : pdst->length; + 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 +1304,11 @@ 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 +1320,13 @@ 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)) - v4l2_planes[0].bytesused = b->bytesused ? - b->bytesused : v4l2_planes[0].length; - else + 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 v4l2_planes[0].bytesused = 0; } diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index e49dc6b..a5790fd 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -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;
The vb2: fix bytesused == 0 handling (8a75ffb) 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: Nicolas Dufresne <nicolas.dufresne@collabora.com> Signed-off-by: Kamil Debski <k.debski@samsung.com> --- drivers/media/v4l2-core/videobuf2-core.c | 29 +++++++++++++++++++++++------ include/media/videobuf2-core.h | 2 ++ 2 files changed, 25 insertions(+), 6 deletions(-)