Blackfin: time-ts: ack gptimer sooner to avoid missing short ints

If the period of a gptimer is fairly low, we might miss an interrupt
by acking it too late (we end up acking the new int as well).

Reported-by: Isabelle Leonardi <i.leonardi@detracom.fr>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c
index 8c9a43daf80f..cdb4beb6bc8f 100644
--- a/arch/blackfin/kernel/time-ts.c
+++ b/arch/blackfin/kernel/time-ts.c
@@ -206,8 +206,14 @@ irqreturn_t bfin_gptmr0_interrupt(int irq, void *dev_id)
 {
         struct clock_event_device *evt = dev_id;
         smp_mb();
-        evt->event_handler(evt);
+        /*
+         * We want to ACK before we handle so that we can handle smaller timer
+         * intervals.  This way if the timer expires again while we're handling
+         * things, we're more likely to see that 2nd int rather than swallowing
+         * it by ACKing the int at the end of this handler.
+         */
         bfin_gptmr0_ack();
+        evt->event_handler(evt);
         return IRQ_HANDLED;
 }