ACER_FTH_OPL
acer_fifo_udma &= ~(ACER_FTH_OPL(chp->channel, drive, 0x3) |
ACER_FTH_OPL(chp->channel, drive, 0x1);
acer_fifo_udma |= ACER_FTH_OPL(chp->channel, drive, 0x2);