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From: Janosch Machowinski <scotch@tzi.de>
To: Vasileios Gkanis <gkanis@cems.umn.edu>
Cc: linux-acpi@vger.kernel.org
Subject: Re: High pitched sound with 2.6.15-ck1 --  Update info
Date: Mon, 30 Jan 2006 22:59:05 +0100	[thread overview]
Message-ID: <43DE8C29.1030007@tzi.de> (raw)
In-Reply-To: <200601301732.47677.gkanis@cems.umn.edu>

Vasileios Gkanis schrieb:
>>Jep,
>>this happens because your power converters starts "singing". If
>>you switch the C-State, you need a different amount of power. So if
>>you have a kernel frequency of 1000 herz, your power converter has
>>to adjust the amount of power 1000 times per second. And because
>>of that it starts "singing". By the way, you can also modulate the sound
>>by scaling your CPU frequency up or down. (Perhaps you could also write
>>a programm, that can play some melody based on this phaenomenon ;-) )
>>
>>    Janosch
> 
> 
> What you said is correct. But, do you know why this happens when I plug in the 
> USB-mouse and not when I plug in the USB-stick?

I would guess that the mouse has a higher power consumption as the 
stick. Try to put in some other usb-devices, that needs a lot of power 
(one of this usb-harddrives without external AC for example) and test it 
  ;-)
   Janosch

      reply	other threads:[~2006-01-30 21:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-27 23:05 High pitched sound with 2.6.15-ck1 -- Update info Vasileios Gkanis
2006-01-28 11:10 ` Janosch Machowinski
2006-01-30 15:32   ` Vasileios Gkanis
2006-01-30 21:59     ` Janosch Machowinski [this message]

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