I had this problem on my HP Folio 13 both on the old Ubuntu 12.10 and the new Ubuntu 13.04.
I have fixed it by editing /etc/default/grub and changing: GRUB_CMDLINE_LINUX="" into: GRUB_CMDLINE_LINUX="acpi_backlight=vendor" And eventually by running: sudo update-grub sudo reboot During this entire operation the screen was completely dark. In order to see anything I had to put a very bright lamp against the screen. I don't see how this bug should be a duplicate of bug #568611. This bug is about the screen back-light not working. Bug #568611 is about the screen controls for increasing and reducing brightness not working. ** This bug is no longer a duplicate of bug 568611 Screen brightness control fails on Dell Studio 1558 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/780625 Title: "acpi_backlight=vendor" needs to be present in kernel cmdline to have backlight working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/780625/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
