uhci-hcd and cpufreq

uhci-hcd and cpufreq

[Thomas Bettler]

I found out the uhci-hcd causes the cpu to work at highest frequecy (according 
to x86info -mhz). If I unload it, cpu frequency dropps from full (1.8GHz) to 
~2/3 (1.1GHz). In both cases top shows 97% or even 99% idle.

1. Why causes uhci-hcd that high frequency at no obiously load?

2. Could this behaviour be stopped or do we have to live with it?

This is what I could find out. But I won't get further since I not a hacker, 
just a user.

Thanks anyway for all your work.
Thomas Bettler

module uhci-hcd and pm

[Thomas Bettler]

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Hello you all

The uhci-hcd module causes the cpu to work at highest frequecy
(according to x86info -mhz). If I unload it, cpu frequency dropps from full
(1.8GHz) to ~2/3 (1.1GHz). In both cases top shows 97% or even 99% idle.
modprobing it again speeds the cpu up again.

So module uhci-hcd prehibits the cpu clock from saving power on notebooks. (At 
least theese with P4-M cpus)

What code forces the cpu to run at high speed? Can I tweak the module to 
permit slower cpu speed?

Thomas Bettler

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