Re: [RESEND] Fast TSC calibration fails with v3.14-rc1 and later

From: Thomas Gleixner
Date: Tue Mar 11 2014 - 09:56:45 EST


On Tue, 11 Mar 2014, Julian Wollrath wrote:

> Am Mon, 10 Mar 2014 11:39:44 +0100 (CET)
> schrieb Thomas Gleixner <tglx@xxxxxxxxxxxxx>:
> > And that definitely does not affect the quick calibration. No idea,
> > except bisecting.
> Ok, via bisecting I found commit
> 73f7d1ca32638028e3271f54616773727e2f9f26 (see below) to be the one that
> introduced this regression.

Interesting. I have no idea what's going on. But maybe can the ACPI
folks shed some light on it.

Thanks,

tglx
>
> Cheers,
> Julian Wollrath
>
> From 73f7d1ca32638028e3271f54616773727e2f9f26 Mon Sep 17 00:00:00 2001
> From: "Lee, Chun-Yi" <joeyli.kernel@xxxxxxxxx>
> Date: Wed, 15 Jan 2014 15:25:48 +0800
> Subject: [PATCH] ACPI / init: Run acpi_early_init() before timekeeping_init()
>
> This is a variant patch from Rafael J. Wysocki's
> ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode()
>
> According to Matt Fleming, if acpi_early_init() was executed before
> efi_enter_virtual_mode(), the EFI initialization could benefit from
> it, so Rafael's patch makes that happen.
>
> And, we want accessing ACPI TAD device to set system clock, so move
> acpi_early_init() before timekeeping_init(). This final position is
> also before efi_enter_virtual_mode().
>
> Tested-by: Toshi Kani <toshi.kani@xxxxxx>
> Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> init/main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/init/main.c b/init/main.c
> index febc511e078a..b6d93c840154 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -565,6 +565,7 @@ asmlinkage void __init start_kernel(void)
> init_timers();
> hrtimers_init();
> softirq_init();
> + acpi_early_init();
> timekeeping_init();
> time_init();
> sched_clock_postinit();
> @@ -641,7 +642,6 @@ asmlinkage void __init start_kernel(void)
>
> check_bugs();
>
> - acpi_early_init(); /* before LAPIC and SMP init */
> sfi_init_late();
>
> if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> --
> 1.9.0
>
>
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