From: Andi Kleen <ak@suse.de>
Date: Sat, 21 Oct 2006 22:38:23 +0000 (+0200)
Subject: [PATCH] x86-64: Fix C3 timer test
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=37b1bccfe75691f5f42bf210d8a349f931896887;p=deliverable%2Flinux.git

[PATCH] x86-64: Fix C3 timer test

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@suse.de>
---

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 1ba5a442ac32..88722f11ca13 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -948,7 +948,7 @@ __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;