Gateway/Emachines Mobile AMD64 Laptops (Arima board)

Coleman Kane cokane at
Wed Jan 19 13:45:12 PST 2005

Hi, I have a Gateway 7422GX mobile athlon64 laptop and have not been
able to get the cpu throttling working. I went through the acpi_cpu.c
code to investigate this, played around for a bit and came up empty.

I looked at the linux cpufreq code and noticed some differences. I also
did a DSDT dump from my ACPI BIOS to figure out the reason why the throttling
doesn't get probed. 

It looks like when the FreeBSD driver searches for it, it looks for some
data in the FADT (FACP) ACPI table to set it up. This information does 
not appear to be in the acpi table at all. Thus, it comes up empty. The
linux ACPI driver seems to look at the structures "_PSS", "_PCT", and "_PPC"
which are links off the Processor object. These -do- exist in my DSDT dumps,
but for some reason I can't seem to write code for the acpi_cpu driver to
even find these and give me results. The information to handle my speed
throttling and voltage throttling would appear to be in here, but I can't
figure it out.

Has anybody else messed with this code, or had these problems yet. I would
like to help out if somebody else has already started working on solving
this issue. I'd really like to get more than an hour out of my battery!

BTW, I'm pretty happy with the laptop otherwise. It runs FreeBSD current
quite well, ACPI enabled and all (which is more than I can say for the HP
and Compaq laptops I've dealt with). Also, any helpful links you may have
would be nice. I run the Free OS User Group at the University of Cincinnati
and we've started seeing a number of these pop up around campus.

Oh yeah, I had to set hw.ata.wc=0 to eliminate some UFS corruption issues.

coleman kane

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