Lemu4 cpu frequency BIOS bug

[bwat47]

I have a lemur ultra (lemu4) with an 2.5ghz i5-3210.

When the lemur ultra is on battery, the bios tells the OS to limit the cpufrequency to a max of 1.70ghz. This value can be checked by looking at: /sys/devices/system/cpu/cpu0/cpufreq/bios_limit. When its plugged back in it changes the max frequency to 2.50ghz. This is expected behaviour with this laptops chipset/bios.

However, under certain conditions it gets "stuck" at 1.70ghz, even after you plug it back in. I've reproduced it this way:

1. Unplug the lemur ultra
2. Suspend to ram
3. While it is still suspended, plug the AC power in, and then resume.

It will then be stuck at a max of 1.70ghz while plugged into AC power, until you unplug and re-plug the AC power. (to verify you can look at cat /sys/devices/system/cpu/cpu0/cpufreq/bios_limit again)