1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 84e6a7e673b7..a2cbb828e92a 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -465,6 +465,21 @@ static int hpet_ioctl_ieon(struct hpet_dev *devp)
         if (irq) {
                 unsigned long irq_flags;
 
+                if (devp->hd_flags & HPET_SHARED_IRQ) {
+                        /*
+                         * To prevent the interrupt handler from seeing an
+                         * unwanted interrupt status bit, program the timer
+                         * so that it will not fire in the near future ...
+                         */
+                        writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
+                               &timer->hpet_config);
+                        write_counter(read_counter(&hpet->hpet_mc),
+                                      &timer->hpet_compare);
+                        /* ... and clear any left-over status. */
+                        isr = 1 << (devp - devp->hd_hpets->hp_dev);
+                        writel(isr, &hpet->hpet_isr);
+                }
+
                 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
                 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
                                                 ? IRQF_SHARED : IRQF_DISABLED;