Bug#470474: cpufrequtils: Laptop limited to 1.2GHz vs 2.2GHz, when no battery, running on AC only.

[User X <userx@xolw.com>]

Hi there,

This bug has been present for a long time, but now (with the latest 
kernel) it seems worst.

I'm currently running 2.6.32-3-686-bigmem in a Squeeze/Sid mix. This is 
a Latitude E6400 with battery and 90watt adapter; in my case, I have 
never removed the battery.

For the last couple of hours, the system has been locking (to 800MHz) 
and unlocking itself every 15 to 30 minutes. When it locks to 800 it 
will ignore any attempt to raise the speed.

Up to today, I used to see this bug manifest when I plugged in the 
65watt adapter, but a restart, while the 65watt was plugged in, would 
fix the problem and unlock the CPU's full speed. Powering on the laptop 
with the 65watt adapter plugged in would lock CPU to slowest speed, only 
a restart would fix. In these cases (before today), with the laptop 
running on batteries, the CPU would be usable to its full speed. I 
thought this was a BIOS issue, but after many BIOS updates, issue 
continued. When I first found this problem, I looked for answers, and 
many people stated that while running Windows, this would not happen, so 
it seems to me that this is a bug on our side. I have not tested this 
Windows claim myself.

Any ideas what else could be causing this behavior?

Please, let me know if there is something I can do to help find this 
annoying bug.

Thanks,


Jim