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

[Thomas Gleixner]

On Thu, 13 Mar 2014, Rafael J. Wysocki wrote:
> I agree, and we need to fix that for 3.14.  Patch is appended.

You beat me by a few minutes. Was about to send out the same, just
with a more spicy changelog :)

> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Subject: ACPI / init: Invoke early ACPI initialization later
> 
> Commit 73f7d1ca3263 (ACPI / init: Run acpi_early_init() before
> timekeeping_init()) optimistically moved the early ACPI initialization
> before timekeeping_init(), but that didn't work, because it broke fast
> TSC calibration for Julian Wollrath on Thinkpad x121e (and most likely
> for others too).  The reason is that acpi_early_init() enables the SCI
> and that interferes with the fast TSC calibration mechanism.
> 
> Thus follow the original idea to execute acpi_early_init() before
> efi_enter_virtual_mode() to help the EFI people for now and we can
> revisit the other problem that commit 73f7d1ca3263 attempted to
> address in the future (if really necessary).

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
 
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