MD_CACHE
mdio.md_options |= MD_CACHE;
mdio.md_options &= ~MD_CACHE;
if (mdiox.md_options & MD_CACHE) {
if (error == 0 && (sc->flags & MD_CACHE) == 0)
sc->flags = mdr->md_options & (MD_ASYNC | MD_CACHE | MD_FORCE |
(mp->flags & MD_CACHE) == 0 ? "off": "on");