T42, Ubuntu 5.10, frequency scaling and fan control

[bcalmac]

I just installed Ubuntu 5.10 on my T42 and I was happy to see that most of the things work out of the box. However,
- min_cpu_frequency is 600 MHz
- the fan runs continously

These two might be somehow related. When I boot in XP the CPU can go down to 24MHz (using SpeedSwitchXP). Why would 600MHz be the min frequency on Linux?

How does the kernel module detect what are the available frequency steps? Can these frequency steps be manually configured?

[kaiser]

AFAIK Linux/the applet for Monitoring and Changing the frequency uses only the Steppings allowed/built-in by Intel.Speedswitch might changes the multiplicator way down then Intel planned and says what is stable.

But cpufreq itself would allow you to specify the frequency in KHz, so I think its just a matter of configuration for the GNOME-Applet.

[pumpkin0]

- min_cpu_frequency is 600 MHz
- the fan runs continously

You can specify any frequency you want, but the CPU never runs below 600MHz. It does not have any mulitplier for extreme underclocks and it should not be stable at such speeds. The only way to go below 600 is changing the FSB.

The fan problem can come from any heat-soucre, including the gfx-chip. Check your temperatures using the ibm-acpi-kernel module.

[nolifer]

When I boot in XP the CPU can go down to 24MHz (using SpeedSwitchXP). Why would 600MHz be the min frequency on Linux?

That is NOT possible. 600MHz is the real min frequency. XP just shows it wrong, if it says 24MHz.