x86: assign IRQs to HPET timers, fix

Looks like IRQ 31 is assigned to timer 3, even without the patch!
I wonder who wrote the number 31. But the manual says that it is
zero by default.

I think we should check whether the timer has been allocated an IRQ before
proceeding to assign one to it.  Here is a patch that does this.

Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Tested-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 593b32cfbc33..22f5fd02ea87 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -852,6 +852,12 @@ int hpet_alloc(struct hpet_data *hdp)
 
                 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
 
+                /* Check if there's already an IRQ assigned to the timer */
+                if (hdp->hd_irq[i]) {
+                        hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
+                        continue;
+                }
+
                 hpet_config = readq(&timer->hpet_config);
                 irq_bitmap = (hpet_config & Tn_INT_ROUTE_CAP_MASK)
                         >> Tn_INT_ROUTE_CAP_SHIFT;