Lewis and Chris, I can confirm that I am experiencing the same behavior as Lewis. I have used both the open source radeon/ati drivers as well as the proprietary fglrx drivers (I'm currently using the fglrx-updates package (2:13.350.1-0ubuntu2) from the Ubuntu repos). I have not yet tried the 14.4 version of fglrx, but can verify that the issue is still present with the proprietary drivers installed.
I'm not sure if this is relevant or not, but when the laptop is unplugged it looks as if the contrast is reduced in line with a decrease in backlight, but the brightness is not similarly reduced. For example, everything looks washed out and there is very little contrast. If you then play with the brightness hotkeys and are able to reduce the backlight to it's lowest settings (reducing the brightness), the contrast/brightness balance is back to normal (at the lowest brightness setting). These are the only two brightness levels that I can get working - full brightness and lowest brightness. I was able to use a workaround detailed here: http://ati.cchtml.com/show_bug.cgi?id=711#c54 to get appropriate contrast/brightness balance on battery at the highest brightness level, but I am still unable to change the backlight settings beyond lowest or highest brightness. Hope that helps. Thank you for looking into this. ** Bug watch added: ATi Linux Platform Bugs #711 http://ati.cchtml.com/show_bug.cgi?id=711 -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1315834 Title: 1002:983d [Acer Aspire V5-122P] Unable to adjust screen brightness Status in “linux” package in Ubuntu: Incomplete Bug description: I am unable to adjust the screen brightness on my Acer Aspire V5-122P. Adjusting brightness in the settings applet has no affect. Adjusting brightness with the keyboard function keys turns the screen on and off seemingly randomly. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-24-generic 3.13.0-24.46 ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9 Uname: Linux 3.13.0-24-generic x86_64 ApportVersion: 2.14.1-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: lewis 2240 F.... pulseaudio /dev/snd/controlC0: lewis 2240 F.... pulseaudio CurrentDesktop: Unity Date: Sun May 4 10:55:50 2014 HibernationDevice: RESUME=UUID=42931b07-a2e1-49a1-9780-874e1d4300b7 InstallationDate: Installed on 2014-04-14 (19 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Beta amd64 (20140326) MachineType: Acer Aspire V5-122P ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic.efi.signed root=UUID=8a594eb2-ccc3-4aa4-a4c5-e872f4033b04 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-24-generic N/A linux-backports-modules-3.13.0-24-generic N/A linux-firmware 1.127 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 07/18/2013 dmi.bios.vendor: Insyde Corp. dmi.bios.version: V2.08 dmi.board.asset.tag: Base Board Asset Tag dmi.board.name: Aspire V5-122P dmi.board.vendor: Acer dmi.board.version: V2.08 dmi.chassis.type: 10 dmi.chassis.vendor: Acer dmi.chassis.version: V2.08 dmi.modalias: dmi:bvnInsydeCorp.:bvrV2.08:bd07/18/2013:svnAcer:pnAspireV5-122P:pvrV2.08:rvnAcer:rnAspireV5-122P:rvrV2.08:cvnAcer:ct10:cvrV2.08: dmi.product.name: Aspire V5-122P dmi.product.version: V2.08 dmi.sys.vendor: Acer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1315834/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
