I recently did a clean install of LinuxMint 19.1 (MATE edition) on my laptop. Since then, pressing the power button inserts a long row of
until I press it again, which leads the insertion of d to stop. Pressing it aditional times mutes and unmutes the volume.
Assigning any actions to the powerbutton via the mate control center (eg, suspend or shutdown) has no effect.
If I boot my laptop from a LinuxMint 18.3 live system using a USB flash drive (the OS I was using before), the power button works as expected.
How can I fix this?
This is on a Lenovo Thinkpad X230 that, as mentioned above, works fine with LinuxMint 18.3.
EDIT: Sorry, I don't have enough reputation to add a comment, so I am adding some information here. I have just verified the sha256 checksum of the ISO image I used and it is correct.