Hi Hans, > From: Hans Verkuil [mailto:hverkuil@xxxxxxxxx] > Sent: Tuesday, February 17, 2015 10:11 AM > > Hi Kamil, > > On 12/16/14 12:36, 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 - VB2_FILEIO_ALLOW_ZERO_BYTESUSED. If the > flag > > is set upon initialization of the queue, the videobuf2 keeps the > value > > of bytesused intact and passes it to the driver. > > What is the status of this patch series? I have to admit that I had forgotten a bit about this patch, because of other important work. Thanks for reminding me :) > Note that io_flags is really the wrong place for this flag, it should > be io_modes. This flag has nothing to do with file I/O. What do you think about adding a separate flags field into the vb2_queue structure? This could be combined with changing io_flags to u8 or a bit field to save space. Best wishes, -- Kamil Debski Samsung R&D Institute Poland > > Regards, > > Hans > > > > > Reported-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx> > > Signed-off-by: Kamil Debski <k.debski@xxxxxxxxxxx> > > --- > > drivers/media/v4l2-core/videobuf2-core.c | 33 > ++++++++++++++++++++++++------ > > include/media/videobuf2-core.h | 3 +++ > > 2 files changed, 30 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/media/v4l2-core/videobuf2-core.c > > b/drivers/media/v4l2-core/videobuf2-core.c > > index d09a891..1068dbb 100644 > > --- a/drivers/media/v4l2-core/videobuf2-core.c > > +++ b/drivers/media/v4l2-core/videobuf2-core.c > > @@ -1276,13 +1276,23 @@ 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 following > > + * io_flag VB2_FILEIO_ALLOW_ZERO_BYTESUSED 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->io_flags & > > + VB2_FILEIO_ALLOW_ZERO_BYTESUSED) > > + pdst->bytesused = psrc->bytesused; > > + else > > + pdst->bytesused = psrc->bytesused ? > > + psrc->bytesused : pdst->length; > > pdst->data_offset = psrc->data_offset; > > } > > } > > @@ -1295,6 +1305,12 @@ 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 following io_flag > > + * VB2_FILEIO_ALLOW_ZERO_BYTESUSED to keep old userspace > > + * applications working. > > */ > > if (b->memory == V4L2_MEMORY_USERPTR) { > > v4l2_planes[0].m.userptr = b->m.userptr; @@ -1306,11 > +1322,16 @@ > > 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->io_flags & > > + VB2_FILEIO_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 bd2cec2..0540bc3 100644 > > --- a/include/media/videobuf2-core.h > > +++ b/include/media/videobuf2-core.h > > @@ -138,10 +138,13 @@ enum vb2_io_modes { > > * by default the 'streaming' style is used by the file io emulator > > * @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer > > * @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each > write() call > > + * @VB2_FILEIO_ALLOW_ZERO_BYTESUSED: the driver setting this flag > will handle > > + * bytesused == 0 as a special case > > */ > > enum vb2_fileio_flags { > > VB2_FILEIO_READ_ONCE = (1 << 0), > > VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1), > > + VB2_FILEIO_ALLOW_ZERO_BYTESUSED = (1 << 2), > > }; > > > > /** > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
