From: Dmitry Torokhov <dtor_core@ameritech.net>
It needs at least the patch below to handle timer wrap-arounds.
arch/i386/kernel/timers/timer_pm.c | 16 +++++++---------
1 files changed, 7 insertions(+), 9 deletions(-)
diff -puN arch/i386/kernel/timers/timer_pm.c~timer_pm-wraparound-fixes arch/i386/kernel/timers/timer_pm.c
--- 25/arch/i386/kernel/timers/timer_pm.c~timer_pm-wraparound-fixes 2003-12-29 12:27:35.000000000 -0800
+++ 25-akpm/arch/i386/kernel/timers/timer_pm.c 2003-12-29 12:27:35.000000000 -0800
@@ -92,28 +92,28 @@ static void mark_offset_pmtmr(void)
{
u32 lost, delta, last_offset;
static int first_run = 1;
- last_offset = offset_tick;
write_seqlock(&monotonic_lock);
+ last_offset = offset_tick;
offset_tick = inl(pmtmr_ioport);
offset_tick &= ACPI_PM_MASK; /* limit it to 24 bits */
/* calculate tick interval */
- delta = (offset_tick - last_offset) & ACPI_PM_MASK;
+ delta = likely(last_offset < offset_tick) ?
+ offset_tick - last_offset : ACPI_PM_MASK - last_offset + offset_tick;
/* convert to usecs */
delta = cyc2us(delta);
/* update the monotonic base value */
- monotonic_base += delta*NSEC_PER_USEC;
+ monotonic_base += delta * NSEC_PER_USEC;
write_sequnlock(&monotonic_lock);
/* convert to ticks */
delta += offset_delay;
- lost = delta/(USEC_PER_SEC/HZ);
- offset_delay = delta%(USEC_PER_SEC/HZ);
-
+ lost = delta / (USEC_PER_SEC / HZ);
+ offset_delay = delta % (USEC_PER_SEC / HZ);
/* compensate for lost ticks */
if (lost >= 2)
@@ -125,8 +125,6 @@ static void mark_offset_pmtmr(void)
first_run = 0;
offset_delay = 0;
}
-
- return;
}
@@ -181,7 +179,7 @@ static unsigned long get_offset_pmtmr(vo
offset = offset_tick;
now = inl(pmtmr_ioport);
now &= ACPI_PM_MASK;
- delta = (now - offset)&ACPI_PM_MASK;
+ delta = likely(offset < now) ? now - offset : ACPI_PM_MASK - offset + now;
return (unsigned long) offset_delay + cyc2us(delta);
}
_