2006-11-01 05:43:46

by Chris Wright

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

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

From: Andi Kleen <[email protected]>

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 <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Chris Wright <[email protected]>

---
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;

--

2006-11-01 06:18:24

by Brown, Len

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

Acked-by: Len Brown <[email protected]>

On Wednesday 01 November 2006 00:34, Chris Wright wrote:
> -stable review patch. If anyone has any objections, please let us know.
> ------------------
>
> From: Andi Kleen <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Chris Wright <[email protected]>
>
> ---
> 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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