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* High pitch noise produced when ACPI processor module loaded
@ 2003-09-26  7:59 Sander Wichers
       [not found] ` <001001c38404$27b959a0$2001a8c0-x1nb5Wr35Zb2xqEl7TXlHQ@public.gmane.org>
  0 siblings, 1 reply; 9+ messages in thread
From: Sander Wichers @ 2003-09-26  7:59 UTC (permalink / raw)
  To: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f

Hi,

My inspiron 8600 (intel centrino/855PM) is producing a strange high pitch
sound which comes from within the machine (definitly not the speakers) when
the acpi processor module get's loaded. When I unload the processor module
the high pitch sound goes away.

Luckily I'm not the only with a dell inspiron having this problem. So far
I've seen bug reports from people with an inspiron 8x00 / and lattitude C840
/ C600 series:
http://www.ussg.iu.edu/hypermail/linux/kernel/0307.1/index.html#2247
http://www.ussg.iu.edu/hypermail/linux/kernel/0305.1/index.html#628

The workarounds displayed in the links above don't do anything with the real
problem....

I've tried to turn of frequency scaling, this doesn't influence anything. I
also tried the apm workaround > no luck either. (apm isn't supported in my
bios)

This isn't normal behavior, is it? The noise is very annoying, it makes you
not want to sit behind the machine! Is there a workaround for this?

thanks,

Sander



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^ permalink raw reply	[flat|nested] 9+ messages in thread
* RE: High pitch noise produced when ACPI processor module loaded
@ 2003-10-06 17:53 Grover, Andrew
       [not found] ` <F760B14C9561B941B89469F59BA3A84702C9300A-sBd4vmA9Se4Lll3ZsUKC9FDQ4js95KgL@public.gmane.org>
  0 siblings, 1 reply; 9+ messages in thread
From: Grover, Andrew @ 2003-10-06 17:53 UTC (permalink / raw)
  To: Pavel Machek, Nate Lawson; +Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f

> [mailto:acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] On Behalf Of 
> Pavel Machek
> > > This unfortunately seems fairly normal; at least all four 
> notebooks I
> > > had for testing produced some kind of cpu-related noise.
> > 
> > It's a *feature*.  I've implemented a Cx driver for FreeBSD and it's
> > useful to be able to tell if the code really is entering 
> the desired state
> > by holding the laptop up to my ear.  I can differentiate 
> all the Cx states
> > but not in the Px states.  :)
> 
> ;-))))))))))))))
> 
> Well, if you have to *hold it up to your ear*, then yes, its a
> feature. Unfortunately, I can hear it while working normally :-(.

Apparently it is a hardware problem. Says someone who knows:

"Well, it's not normal, but it means they used cheap capacitors. This is
known as the acoustic noise issue. It's related to PCB vibration as a
result of the piezo electric effect on the caps. What is the timer tick
frequency? For Windows, it's 15.6ms or 10ms by default, but can go as
frequent as 1ms. The 1ms gives a nice 1kHz tone. It's related to the
voltage change of C4 exit."

Since Linux (2.6 anyways) uses a 1ms timer tick, this will be seen more
frequently on Linux. If it's really a bother, using a longer tick might
be something to try...

Regards -- Andy


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^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2003-10-06 17:59 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-09-26  7:59 High pitch noise produced when ACPI processor module loaded Sander Wichers
     [not found] ` <001001c38404$27b959a0$2001a8c0-x1nb5Wr35Zb2xqEl7TXlHQ@public.gmane.org>
2003-09-26 17:06   ` Nate Lawson
     [not found]     ` <20030926100512.X64952-Y6VGUYTwhu0@public.gmane.org>
2003-10-02 11:12       ` Pavel Machek
2003-10-05  9:35         ` Sander Wichers
     [not found]           ` <000401c38b23$fddef730$2401a8c0-laDPoAWcecs@public.gmane.org>
2003-10-05 10:24             ` Pavel Machek
     [not found]               ` <20031005102452.GA321-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org>
2003-10-06 16:41                 ` Nate Lawson
     [not found]                   ` <20031006093904.K3158-Y6VGUYTwhu0@public.gmane.org>
2003-10-06 17:12                     ` Pavel Machek
  -- strict thread matches above, loose matches on Subject: below --
2003-10-06 17:53 Grover, Andrew
     [not found] ` <F760B14C9561B941B89469F59BA3A84702C9300A-sBd4vmA9Se4Lll3ZsUKC9FDQ4js95KgL@public.gmane.org>
2003-10-06 17:59   ` Pavel Machek

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