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authorLinus Torvalds <torvalds@linux-foundation.org>2008-09-06 19:33:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-06 19:33:26 -0700
commitf5325225658737e6c9cb8e24373e2c281a90be2a (patch)
treef1daf00b394b543876b6ffbfd67c050c3bb1b114 /arch
parent4747832b56a95dbeb0cef4714e6fcc766eed0a95 (diff)
parent4ab6a219113197425ac112e35e1ec8062c69888e (diff)
Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource, acpi_pm.c: check for monotonicity clocksource, acpi_pm.c: use proper read function also in errata mode ntp: fix calculation of the next jiffie to trigger RTC sync x86: HPET: read back compare register before reading counter x86: HPET fix moronic 32/64bit thinko clockevents: broadcast fixup possible waiters HPET: make minimum reprogramming delta useful clockevents: prevent endless loop lockup clockevents: prevent multiple init/shutdown clockevents: enforce reprogram in oneshot setup clockevents: prevent endless loop in periodic broadcast handler clockevents: prevent clockevent event_handler ending up handler_noop
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/hpet.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 59fd3b6b130..73deaffadd0 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -210,8 +210,8 @@ static void hpet_legacy_clockevent_register(void)
/* Calculate the min / max delta */
hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
&hpet_clockevent);
- hpet_clockevent.min_delta_ns = clockevent_delta2ns(0x30,
- &hpet_clockevent);
+ /* 5 usec minimum reprogramming delta. */
+ hpet_clockevent.min_delta_ns = 5000;
/*
* Start hpet with the boot cpu mask and make it
@@ -270,15 +270,22 @@ static void hpet_legacy_set_mode(enum clock_event_mode mode,
}
static int hpet_legacy_next_event(unsigned long delta,
- struct clock_event_device *evt)
+ struct clock_event_device *evt)
{
- unsigned long cnt;
+ u32 cnt;
cnt = hpet_readl(HPET_COUNTER);
- cnt += delta;
+ cnt += (u32) delta;
hpet_writel(cnt, HPET_T0_CMP);
- return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0) ? -ETIME : 0;
+ /*
+ * We need to read back the CMP register to make sure that
+ * what we wrote hit the chip before we compare it to the
+ * counter.
+ */
+ WARN_ON((u32)hpet_readl(HPET_T0_CMP) != cnt);
+
+ return (s32)((u32)hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0;
}
/*