Sometime in the last couple of weeks the brightness controls on my Thinkpad x300 stopped working.

I fixed it by creating /etc/modprobe.d/thinkpad_acpi.conf and putting this line in it:

options thinkpad\_acpi hotkey=enable,0xfdffff

Then you have to remove and reinstall the module to read the new options:<pre>sudo rmmod thinkpad_acpi
sudo modprobe thinkpad_acpi</pre>I’m not sure I’m getting all the brightness I should, but at least the control works to put the brightness up to make the screen readable.

Whine: This isn’t the first time some part of the interface between Ubuntu and my laptop has broken due to an update. I can sympathize with the developers and the difficulty of testing all laptops out there, but I can sympathize more with the user who isn’t going to put up with an O/S that mysteriously starts and stops working as updates are installed.