Some of this was touched on at Fedora on Macbook.
PowerTOP is a useful tool to get more battery life out of a laptop. It makes the difference of several hours of battery life, so it's a useful thing to install.
Install and enable it:
sudo dnf install powertop sudo systemctl enable powertop.service sudo systemctl start powertop.service
The service runs
powertop --auto-tune which automatically sets most tunables to their "Good" state, for maximum battery life.
But sometimes it doesn't work well, especially with USB mice.
It perplexed me for a while why my USB mouse on a laptop would deactivate itself randomly (its LED turns off, and the mouse doesn't work until you click one of the buttons, and then it will power itself off again after a couple minutes...). Unplugging the USB mouse and plugging it back in would fix the problem and it would no longer auto-suspend itself. I was checking
/var/log/messages and all the usual suspects until I realized it was PowerTOP that was the problem.
powertop --auto-tune gets run, every USB device attached at the time gets the
auto power management profile set, meaning they deactivate themselves to save power. On a keyboard or most other devices that's probably fine, but a mouse isn't. My workarounds have been to either not connect my USB devices until after my laptop boots into my desktop environment, or to unplug and replug the USB mouse after the fact.
I can't find a good "official" way to work around the problem. Google suggests editing things in
/etc/laptop-mode but that isn't a thing in Fedora, and others have suggested setting up udev rules for your USB device, but that doesn't work either. I even found this Power Management Guide for Fedora 19 which pointed me to
powertop2tuned to override powertop rules, but that didn't help me either.
My hacky work-around: make a shell script that starts on user log-in, that undoes PowerTOP's change to the USB device.
sudo powertopand go to the Tunables tab.
When toggling it, PowerTOP shows a message of what it did to toggle it, which looks like:
echo 'on' > '/sys/bus/usb/devices/2-22.214.171.124/power/control'
Create a shell script that does that job. I made mine at
#!/bin/sh # Disable USB auto-suspend for my mouse on startup sleep 5; MOUSE="/sys/bus/usb/devices/2-126.96.36.199/power/control"; if [ -f "$MOUSE" ]; then echo 'on' > $MOUSE; fi
kirsle ALL=(ALL) NOPASSWD: /home/kirsle/bin/powertop-fix
sudo /home/kirsle/bin/powertop-fixstart automatically using your desktop's session management settings (e.g. Xfce Sessions and Startup -> Application Autostart).