The bug is fixed in trusty. I updated system last week and all woks with 331+ drivers
** Changed in: nvidia-prime (Ubuntu) Status: Confirmed => Fix Released -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to nvidia-prime in Ubuntu. https://bugs.launchpad.net/bugs/1342786 Title: Brightness OSD killed by nvidia-prime Status in “nvidia-prime” package in Ubuntu: Fix Released Bug description: Installed Ubuntu 14.04 64 bit on an Acer Aspire 5750ZG Nvidia Optimus laptop. There was no issue with brightness until I installed the nvidia-prime package: I could adjust brightness in System Settings as well as with the brightness keys (Fn+left/right arrows). The brightness on-screen display used to appear fine on the screen while adjusting brightness with the function keys. After I had installed nvidia-prime, I could still adjust brightness in System Settings but no longer with the brightness keys. The osd disappeared, too. Adding acpi_osi=Linux to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub fixed the brightness keys but did not bring back the osd. Removing nvidia-prime did not help. The osd was lost for good. Reinstalled Ubuntu 14.04 formatting the / partition and now everything is fine again. Installed bumblebee with nvidia-331 and still everything is fine. The nvidia-prime packages seems to do something that breaks both the brightness keys (which can be fixed with acpi_osi=Linux) and the osd (which I could not bring back). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-prime/+bug/1342786/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp