[PATCH 41/61] x86-64: Fix C3 timer test

From: Chris Wright
Date: Wed Nov 01 2006 - 00:44:35 EST


-stable review patch. If anyone has any objections, please let us know.
------------------

From: Andi Kleen <ak@xxxxxxx>

There was a typo in the C3 latency test to decide of the TSC
should be used or not. It used the C2 latency threshold, not the
C3 one. Fix that.

This should fix the time on various dual core laptops.

Signed-off-by: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>

---
arch/x86_64/kernel/time.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-2.6.18.1.orig/arch/x86_64/kernel/time.c
+++ linux-2.6.18.1/arch/x86_64/kernel/time.c
@@ -960,7 +960,7 @@ __cpuinit int unsynchronized_tsc(void)
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
#ifdef CONFIG_ACPI
/* But TSC doesn't tick in C3 so don't use it there */
- if (acpi_fadt.length > 0 && acpi_fadt.plvl3_lat < 100)
+ if (acpi_fadt.length > 0 && acpi_fadt.plvl3_lat < 1000)
return 1;
#endif
return 0;

--
-
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