outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
outb(probe_val, PIC_MASTER_IMR);
new_val = inb(PIC_MASTER_IMR);
if (new_val != probe_val) {
printk(KERN_INFO "Using NULL legacy PIC\n");
legacy_pic = &null_legacy_pic;
outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
outb(probe_val, PIC_MASTER_IMR);
new_val = inb(PIC_MASTER_IMR);
if (new_val != probe_val) {
printk(KERN_INFO "Using NULL legacy PIC\n");
legacy_pic = &null_legacy_pic;