linux-kernel - Re: Mystery clicking under keyboard, 3.x only, SSD only

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Date:	Mon, 12 Dec 2011 12:27:53 -0500
From:	Bill Gribble <grib@...lgribble.com>
To:	"Alexander E. Patrakov" <patrakov@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Mystery clicking under keyboard, 3.x only, SSD only

On Mon, 2011-12-12 at 23:10 +0600, Alexander E. Patrakov wrote:
> This clicking can be related to the events when the device goes to deep 
> powersaving levels. Fluctuations in the consumed current can lead to 
> audible clicks due to bad screening of audio wires, loose ferrite cores 
> in the coils, magnetostriction effect, etc.
> 
> You can test this theory by running several copies of "yes > /dev/null" 
> and thus eating 100% CPU. If this eliminates the clicking effect, then 
> my guess is correct and you have to disable some of the deepest 
> powersaving states to remove the clicks.

Got it in one!  Causing 100% CPU utilization does indeed stop the
clicking.  I will look for power saving settings that I can control. 

Thanks,
Bill Gribble


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