You can try the following utilities to see whether CPUs are occupied before and after USB devices are plugged in
1. top - check whether any processes is running 2. watch -n1 cat /proc/interrupts - check whether any interrupts are generated at abnormal rates 3. powertop - more details of power and frequencies of the CPUs. You may also be able to tune USB controllers and devices. Note autosuspending mouses or keyboards can cause wake-up delays. You may also want to try Ubuntu & Kubuntu live images. If you can duplicate the same problems in the live sessions, you can run apport there too. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1895378 Title: cpu frequency stuck to max when pugging USB device Status in linux package in Ubuntu: Confirmed Bug description: When I start my laptop with AC plugged in, the CPU frequency oscillates around 1.5Ghz, but as soon as I plug some USB device, like an external mouse, the frequency goes up to the max (3.2Ghz) and stays there, even though the system monitor tells me that no app is eating CPU power. (see picture) If I unplug the mouse, this doesn't go back to normal: still stuck max frequency. If I start my laptop with mouse already plugged in, it starts normally (scalable frequency around 1.5Ghz), if I unplug the mouse, still good, but if I plug the mouse again, it jumps to max frequency and stays there. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1895378/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
