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-rw-r--r--drivers/char/hpet.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index a0a1829d3198..995d2ff487d9 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -479,6 +479,21 @@ 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;