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    Subject[PATCH 4.4 072/108] vb2: V4L2_BUF_FLAG_DONE is set after DQBUF
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Ricardo Ribalda <ricardo.ribalda@gmail.com>

    commit 3171cc2b4eb9831ab4df1d80d0410a945b8bc84e upstream.

    According to the doc, V4L2_BUF_FLAG_DONE is cleared after DQBUF:

    V4L2_BUF_FLAG_DONE 0x00000004 ... After calling the VIDIOC_QBUF or
    VIDIOC_DQBUF it is always cleared ...

    Unfortunately, it seems that videobuf2 keeps it set after DQBUF. This
    can be tested with vivid and dev_debug:

    [257604.338082] video1: VIDIOC_DQBUF: 71:33:25.00260479 index=3,
    type=vid-cap, flags=0x00002004, field=none, sequence=163,
    memory=userptr, bytesused=460800, offset/userptr=0x344b000,
    length=460800

    This patch forces FLAG_DONE to 0 after calling DQBUF.

    Reported-by: Dimitrios Katsaros <patcherwork@gmail.com>
    Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
    Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
    Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/media/v4l2-core/videobuf2-v4l2.c | 6 ++++++
    1 file changed, 6 insertions(+)

    --- a/drivers/media/v4l2-core/videobuf2-v4l2.c
    +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
    @@ -593,6 +593,12 @@ static int vb2_internal_dqbuf(struct vb2
    b->flags & V4L2_BUF_FLAG_LAST)
    q->last_buffer_dequeued = true;

    + /*
    + * After calling the VIDIOC_DQBUF V4L2_BUF_FLAG_DONE must be
    + * cleared.
    + */
    + b->flags &= ~V4L2_BUF_FLAG_DONE;
    +
    return ret;
    }


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