Previously, drm_get_resource_start() and drm_get_resource_len() would

    allocate the resource RF_ACTIVE, pull out the appropriate value, and
    return it. However, allocating large framebuffers RF_ACTIVE would run
    the system out of KVA, and this also left open the possibility of the
    resource getting moved after getting the offset. Instead, when either
    of these are called, allocate the resource if it isn't allocated
    already (non-RF_ACTIVE) and store it in the DRM device, to be cleaned
    up on lastclose.