udl_fb_buf_write
r = (sc->udl_fb_buf_write)(sc, buf, x, ly, font->fontwidth);
r = (sc->udl_fb_buf_write)(sc, buf, x_cur, y, block);
int udl_fb_buf_write(struct udl_softc *, uint8_t *, uint32_t,
sc->udl_fb_buf_write = udl_fb_buf_write;
sc->udl_fb_buf_write = udl_fb_buf_write_comp;
int (*udl_fb_buf_write)