I have the same problem. My cpu Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz. When on battery max_freq is locked down to min_freq, which is 800MHz. I'm using a fully updated Ubuntu 13.04. The problem was not there right after a fresh installation and appeared after some upgrade during the previous days.
I noticed that the file /sys/devices/system/cpu/cpu0/cpufreq/bios_limit contains '2701000' on AC and '800000' on battery. Adding the boot parameter 'processor.ignore_ppc=1' apparently fixes the issue, i.e. the bios_limit is '2701000' even on battery and the governor can use the full frequency range: but unfortunately the system remains slow on battery, it's like the frequency is ramped up very lazily. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1174169 Title: Minimum and maximum cpu frequency are equal To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1174169/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
