[Qemu-devel] [PATCH 1/2] arm_timer: reload timer when enabled

[Rabin Vincent <rabin@rab.in>]

Reload the timer when TimerControl is written, if the timer is to be
enabled.  Otherwise, if an earlier write to TimerLoad was done while
periodic mode was not set, s->delta may incorrectly still have the value
of the maximum limit instead of the value written to TimerLoad.

This problem is evident on versatileap on current linux-next, which
enables TIMER_CTRL_32BIT before writing to TimerLoad and then enabling
periodic mode and starting the timer.  This causes the first periodic
tick to be scheduled to occur after 0xffffffff periods, leading to a
perceived hang while the kernel waits for the first timer tick.

Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 hw/arm_timer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/hw/arm_timer.c b/hw/arm_timer.c
index 9fef191..5b6947a 100644
--- a/hw/arm_timer.c
+++ b/hw/arm_timer.c
@@ -113,7 +113,7 @@ static void arm_timer_write(void *opaque, target_phys_addr_t offset,
         case 1: freq >>= 4; break;
         case 2: freq >>= 8; break;
         }
-        arm_timer_recalibrate(s, 0);
+        arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
         ptimer_set_freq(s->timer, freq);
         if (s->control & TIMER_CTRL_ENABLE) {
             /* Restart the timer if still enabled.  */
-- 
1.7.0.4