Re: IO-APIC on nforce2 [PATCH] + [PATCH] for nmi_debug=1 + [PATCH]for idle=C1halt, 2.6.5

[Maciej W. Rozycki]

On Thu, 29 Apr 2004, Ross Dickson wrote:

> > Do you really think so?  I think there may be a resonance occuring, even with 
> > this new BIOS.  I plugged in new headphones into my nforce2 onboard sound, and 
> > get a high pitched noise.  Now here is where it gets weird:  This noise does 
> > not occur on boot until sometime after the IDE driver is loaded.  I also 
> > believe it varies under a high load.  If you disable C1 disconnect, it's gone.  
> > Also I've heard a high pitched noise at certain times coming right from the 
> > copmuter (very faint, but I do have very good hearing, I can even hear a hush 
> > sounding from my router.  my brother was quite astonished when I pointed that 
> > out)  I try to distinguish whats doing it.  It could be the hard drive.  But 
> > when I found the other sound in the head phones, I found that the sound varies 
> > almost in unison with the sound coming from the computer.  Maybe the IDE or 
> > hard drive is related, but it is too much related to C1 disconnect.
> 
> I think I might break out my oscilloscope this weekend and have a look at how 
> clean the supply rails are around the cpu and northbridge and southbridge. 
> Who knows I might get lucky and see some unexpected ripple or spikes.

 Not necessarily related to the PSU, but the noise may actually be the
reason of spurious timer interrupts.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@xxxxxxxxxxxxx, PGP key available        +
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