Thanks Christopher M. Penalver (penalvch), I downloaded the updated bios and created the boot usb.
I then changed my BIOS boot mode to Legacy in order to be able to boot from the USB. I must have done something wrong for my UBS drive was not bootable. Result: I was UNABLE to update the BIOS. I then changed boot mode back to UEFI and, to my surprise, the notebook booted to a perfectly normal screen brightness and fully working brightness function keys! Not sure what or IF I should do something now... It seems the problem was not due to the BIOS version. I am unable to reproduce the problem. If have some advice I can follow or when can just dismiss this bug report? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1372399 Title: [XPS 13 L322X] Cannot adjust screen brightness To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-trusty/+bug/1372399/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
