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Interl XScale pxa cpufreq driver

DISCUSSION Young-Jin Kim 5 participants 5 messages Mar 22, 2004

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Young-Jin Kim

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Hi,
I know there is no cpufreq driver which supports XScale PXA processor.
If I want to build a DVS system using the cpufreq infra on a PXA board,
how much work should I need? This work may include writing a PXA cpufreq driver, adding a module for changing the voltage, etc.
And, I want to know if there is a routine of changing the supply voltage in speedstep-ich for Intel Mobile Pentium 4. In fact I cannot see well.
Any comment will be helpful to me.
Regards,

Young-Jin Kim

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#1 lore raw
Quoted 2 lines · Young-Jin Kim

Hi,
I know there is no cpufreq driver which supports XScale PXA processor.

There is one. You could have a look at the kernel sources of the ARM Linux project or the Familiar distribution. I worked on a project that involved DVS on a PXA board. At least the frequency scaling part should be freely available. For voltage scaling, we used a proprietary driver. The only problem I encountered was some instability of the USB driver when many frequency changes were done.

Stefan

#2 lore raw
Quoted 6 lines · Stefan Buettcher
Quoted 2 lines · Young-Jin Kim

Hi,
I know there is no cpufreq driver which supports XScale PXA processor.

There is one. You could have a look at the kernel sources of the ARM Linux project or the Familiar distribution.

It's not part of the ARM kernels, and if its sitting in the handhelds.org CVS, I don't expect it ever to be. handhelds.org CVS is a dumping ground for random stuff and is a failure as far as the Linux kernel and Open Source goes.

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Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core
#3 lore raw
In reply to Young-Jin Kim
Quoted 2 lines · Young-Jin Kim

And, I want to know if there is a routine of changing the supply voltage in speedstep-ich for Intel Mobile Pentium 4. In fact I cannot see well.

There is no (standardized) way to change default setting of the two core voltages that can be applyed to a mobile pentium 4.

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Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.