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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-09-07 04:33:26 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-09-07 04:33:26 +0200 |
| commit | f5325225658737e6c9cb8e24373e2c281a90be2a (patch) | |
| tree | f1daf00b394b543876b6ffbfd67c050c3bb1b114 /arch/x86/kernel | |
| parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiw... (diff) | |
| parent | clocksource, acpi_pm.c: check for monotonicity (diff) | |
| download | linux-f5325225658737e6c9cb8e24373e2c281a90be2a.tar.xz linux-f5325225658737e6c9cb8e24373e2c281a90be2a.zip | |
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/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/hpet.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 59fd3b6b1303..73deaffadd03 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; } /* |