Annoying whitenoise sound coming from snd_hda enabled chipset

[Yoshihiro Ota]

On Wed, 29 Jul 2009 19:06:27 -0400
Ben Kaduk <minimarmot at gmail.com> wrote:

> 2009/7/28 Yoshihiro Ota <ota at j.email.ne.jp>:
> > On Fri, 24 Jul 2009 01:23:18 +0200
> > Ståle Lyngaas <staale at lyngaas.com> wrote:
> >
> >> On Sat, Feb 21, 2009 at 11:01 AM, Garrett Cooper<yanefbsd at gmail.com> wrote:
> >> >    I don't know how else to describe it, but when I turn up my
> >> > speakers enough (50%+) and don't have any sound playing, I hear a
> >> > whitenoise hiss coming out of them. When I change webpages (nvidia
> >> > driver is GIANT locked) or do something else kernel intensive it stops
> >> > for a brief second, but apart from that it's an annoying trill sound
> >> > almost like a mosquito humming around me waiting to be swatted.
> >>
> >> I suspect this is due to the CPU executing the HLT instruction.
> >>
> >> Try running the following command:
> >>     sysctl machdep.cpu_idle_hlt=0
> >>
> >> --
> >> Ståle Lyngaas
> >
> > I couldn't find such a sysctl.
> > The close one was machdep.cpu_hlt.
> 
> Setting machdep.idle from acpi to spin make my problems go away.
> (None of the other options (mwait, mwait_hlt, hlt, acpi) helped.)
> 
> -Ben Kaduk

After machdep.idle, the sound went away here, too.
The laptop just got hotter, however.

It looks this sound only comes from one of two laptop I have.

I probabry live with the sound as it is the mid. summer now.
Thanks for your info, though.

Hiro