CPU frequency scaling insanity

[disco_stud]

Greetings and well met. Running Debian Etch on a Intel T2400 core duo Z61t. Everything works fine except for one thing:

If I unplug the battery pack and leave the laptop on AC adapter only, the speed of the CPU suddenly drops to low and there is no way to bring it up again. Plug the battery back in and the speed climbs up again. I'm using the standard performance/dynamic regulators, it makes no difference whether they are in the kernel or userspace (powernowd, powersaved, etc.).

The usual searching and googling reveals that the problem is widespread and not confined to Thinkpads or any specific Linux distribution, kernel module or setup. If this the expected Speedstep behaviour I'm having a hard time to call it a feature, given that Lenovo itself suggests to unplug the battery pack when running on AC in order to avoid excessive heat exposure and prolong the life of the battery.

So I guess my question is: what's going on here? I didn't buy a 1.8Ghz core duo to see it perform like a Pentium 3.

Your thoughts will be appreciated. Outputs of cpufreq-info and what-not are available on request.

[whizkid]

Welcome to the forum!

You might want to ask a moderator move this thread to the Linux discussions for a more knowledgeable audience. I run Fedora on my T60, but have not tried using it without the battery.

[Paul Unger]

You can change SpeedStep setting in the BIOS for different power configurations (i.e., battery, AC, both). Have you tried that?