Re: High pitch noise when ACPI processor module is loaded.

From: Robert Hancock
Date: Sat Jan 23 2010 - 15:42:45 EST

On 01/23/2010 02:12 PM, Rafael J. Wysocki wrote:
Messages about ACPI should be CCed to linux-acpi@xxxxxxxxxxxxxxx (added).

On Saturday 23 January 2010, Justin Piszcz wrote:

When I do not load the ACPI processor module, there is no high pitch
noise. When I load the ACPI processor module (so I can utilize Turbo
Boost), Linux makes the system emit a high pitch noise.

The same system, running Windows 7 does not emit any noise.

Is there something wrong with the ACPI processor module or its
implementation on i5/i7 CPUs?

May not be anything "wrong", but some systems do have an issue with the voltage regulator circuitry where it can make noise with certain combinations of power draw and wakeup rates (causing rapid current draw fluctuations) where some of the components can resonate and make noise.

What does powertop report for this system? It might show some useful info.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at