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I booted my laptop docked to a USB keyboard and external monitor. I've used it in this setup very recently and it was fine. Today, the USB keyboard is sometimes ignoring a key press.

It happened a couple of times when I hit Home. But if I test it specifically, the key works fine.

I thought maybe I was hitting it wrong after adjusting from the smaller laptop keyboard. But then it clearly dropped a few characters when I was starting to type something.

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The problem is I have powertop.service enabled. Enabling this means powertop --autotune runs at startup and enables most extra power-saving features. It's very useful to improve the battery life.

Unfortunately this includes usb autosuspend on all (?) usb devices which are connected at the time. Linux deliberately defaults to not enabling autosuspend on input devices, due to reports like this, including my report at the time on what was most likely the same keyboard. (Logitech Internet 350).

Workaround

If you booted with the USB keyboard plugged in, just unplug it and then plug it back in again. This clears the configuration set by powertop --autotune.

A more "correct" solution would be to go through each command recommended by powertop, and create a boot script which runs all of them except the USB autosuspend one.

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