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| author | Pavel Emelyanov <xemul@openvz.org> | 2009-02-04 13:40:31 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-05 01:04:16 +0100 |
| commit | a6a95406c676ffe4f9dee708eb404a17c69f7fdd (patch) | |
| tree | d38f5d1e266024e6df16f5499609ab8711b71d27 | |
| parent | b1792e367053968f2ddb48bc911d314143ce6242 (diff) | |
| download | linux-a6a95406c676ffe4f9dee708eb404a17c69f7fdd.tar.gz linux-a6a95406c676ffe4f9dee708eb404a17c69f7fdd.tar.bz2 linux-a6a95406c676ffe4f9dee708eb404a17c69f7fdd.zip | |
x86: fix hpet timer reinit for x86_64
There's a small problem with hpet_rtc_reinit function - it checks
for the:
hpet_readl(HPET_COUNTER) - hpet_t1_cmp > 0
to continue increasing both the HPET_T1_CMP (register) and the
hpet_t1_cmp (variable).
But since the HPET_COUNTER is always 32-bit, if the hpet_t1_cmp
is 64-bit this condition will always be FALSE once the latter hits
the 32-bit boundary, and we can have a situation, when we don't
increase the HPET_T1_CMP register high enough.
The result - timer stops ticking, since HPET_T1_CMP becomes less,
than the COUNTER and never increased again.
The solution is (based on Linus's suggestion) to not compare 64-bits
(on 64-bit x86), but to do the comparison on 32-bit signed
integers.
Reported-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/kernel/hpet.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 64d5ad0b8add..c761f914430a 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -1075,7 +1075,7 @@ static void hpet_rtc_timer_reinit(void) hpet_t1_cmp += delta; hpet_writel(hpet_t1_cmp, HPET_T1_CMP); lost_ints++; - } while ((long)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0); + } while ((s32)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0); if (lost_ints) { if (hpet_rtc_flags & RTC_PIE) |