depends on the discarding policy.
Applications can get and set the number of buffers used internally by
-the driver with the :ref:`VIDIOC_G_PARM <VIDIOC_G_PARM>` and
+the driver with the :ref:`VIDIOC_G_PARM` and
:ref:`VIDIOC_S_PARM <VIDIOC_G_PARM>` ioctls. They are optional,
however. The discarding policy is not reported and cannot be changed.
For minimum requirements see :ref:`devices`.