Messages in this thread | | | Date | Mon, 10 Mar 2008 13:49:15 +0100 | From | Pierre Ossman <> | Subject | Re: [linux-pm] [PATCH] cpuidle: avoid singing capacitors |
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On Mon, 10 Mar 2008 11:00:08 +0100 Pavel Machek <pavel@ucw.cz> wrote:
> On Sun 2008-03-09 15:16:59, Pierre Ossman wrote: > > 2. uhci_hcd driver > > > > USB is somehow involved in this problem. Unloading the uhci_hcd driver almost entirely kills the noise on a 1000 HZ NO_HZ kernel. On a 100 HZ, no NO_HZ kernel, the effect is very small, but still there. > > USB keeps processor out of C3 in many cases. >
I figured that was the case. But I did not see any difference in powertop.
> > 4. Battery and AC > > > > The noise increases with the battery present and also when the AC supply is removed. > > > > On battery, some machines swap C3 for "secret" C4, which is slower but > saves power.
I guess the only way to find out is to disassemble the DSDT. Exposing myself to such concentrations of ACPI is not an appealing project. :/
-- -- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org PulseAudio, core developer http://pulseaudio.org rdesktop, core developer http://www.rdesktop.org
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