cached_21
cached_21 |= 1 << d->irq;
cached_21 &= ~(1 << d->irq);
cached_21 &= ~(1 << 2);
outb(cached_21, 0x21);
cached_21 |= 1 << d->irq;
outb(cached_21, 0x21);
outb(cached_21,0x21);