Hrtimer init problem

[tzuck]

Hi.
I use kernel 2.6.19 supplied by montavista.
I added a kernel module that starts a hrtimer.
I needed the timer to work in hard irq context so I used the following code to init the timer
void EnableMyHrTimer(int CycleTimeInMicro)
{
ktime_t tim;

MyHrTimer.function = GpioReadWrite;
MyHrTimer.cb_mode = HRTIMER_CB_IRQSAFE;
MyHrTimer.expires = ktime_set( 0, CycleTimeInMicro * 1000 );

hrtimer_init(&MyHrTimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);

hrtimer_start(&MyHrTimer, MyHrTimer.expires, HRTIMER_MODE_ABS);

}

the problem is that when I start the timer the system looks stuck for a few seconds and the timer goes crazy, and then it starts to work fine.
I blink some leds inside the timer and it seems that the timer rate in the beginning is very high.

please advice.

[Rubberman]

I don't know if this will help. It is from the kernel hrtimer.h file:

/*
 * clock_was_set() is a NOP for non- high-resolution systems. The
 * time-sorted order guarantees that a timer does not expire early and
 * is expired in the next softirq when the clock was advanced.
 */
#define clock_was_set()         do { } while (0)

It seems to imply that it may be useful in these situations. IE, you start the timer, then call clock_was_set(). This is just a guess, until I find out more about high-res timers in the kernel.