vtbuf_set_mark
int vtbuf_set_mark(struct vt_buf *vb, int type, int col, int row);
vtbuf_set_mark(vb, VTB_MARK_START, 0, 0);
vtbuf_set_mark(&vw->vw_buf, VTB_MARK_MOVE,
if (vtbuf_set_mark(&vw->vw_buf, mark, vd->vd_mx / vf->vf_width,