I think this is the same BIOS bug we met in bug 1315972. It's reported that it's fixed with BIOS 92.12 and it's also the BIOS we used for pre- installed certification. Have you updated the BIOS to a new version?
** Changed in: hwe-next Status: New => Incomplete ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete ** Changed in: hwe-next Importance: Undecided => Medium -- 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/1409625 Title: [HP EliteBook 725 G2 Notebook PC] brightness could not be controlled by the function key and the slider of "System settings -> Brightness and Lock" but sysfs works Status in HWE Next Project: Incomplete Status in linux package in Ubuntu: Incomplete Bug description: HP EliteBook 725 G2 Notebook PC (CID 201405-15214) updated Ubuntu 14.04.1 3.13.0-43-generic #72 Steps to reproduce the bug: 1. install 12.04.3 on this machine 2. update the system via update manager to make the system up-to-date 3. click the upper-right indicator to launch the "System settings -> Brightness and Lock" applet 4. try to adjust the brightness slider to control the brightness 5. try to adjust the brightness by the function key fn+F8 or fn+F9 Expected result: The brightness could be adjusted Actual result: screen brightness has no response More information: brightness has no response by using this command: echo 4 | sudo tee -a /sys/class/backlight/acpi_video0/brightness brightness HAS response by using this command: echo 4 | sudo tee -a /sys/class/backlight/radeon_bl0/brightness ------------------------ ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-43-generic 3.13.0-43.72 ProcVersionSignature: Ubuntu 3.13.0-43.72-generic 3.13.11.11 Uname: Linux 3.13.0-43-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.6 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: ubuntu 1417 F.... pulseaudio /dev/snd/controlC0: ubuntu 1417 F.... pulseaudio CurrentDesktop: Unity Date: Mon Jan 12 02:50:55 2015 HibernationDevice: RESUME=UUID=e24b803a-e217-4d6d-a35c-dbe0c033966a InstallationDate: Installed on 2015-01-08 (3 days ago) InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2) IwConfig: eth0 no wireless extensions. lo no wireless extensions. MachineType: Hewlett-Packard HP Licrice ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-43-generic root=UUID=c1e0a265-8c75-4427-ad25-f0c76f003ce7 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-43-generic N/A linux-backports-modules-3.13.0-43-generic N/A linux-firmware 1.127.11 RfKill: 0: hci0: Bluetooth Soft blocked: no Hard blocked: no SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 09/03/2014 dmi.bios.vendor: Hewlett-Packard dmi.bios.version: M84 Ver. 97.35 dmi.board.asset.tag: Base Board Asset Tag dmi.board.name: 221D dmi.board.vendor: Hewlett-Packard dmi.board.version: KBC Version 63.14 dmi.chassis.asset.tag: 73612P10CU dmi.chassis.type: 10 dmi.chassis.vendor: Hewlett-Packard dmi.modalias: dmi:bvnHewlett-Packard:bvrM84Ver.97.35:bd09/03/2014:svnHewlett-Packard:pnHPLicrice:pvrA3009CD10002:rvnHewlett-Packard:rn221D:rvrKBCVersion63.14:cvnHewlett-Packard:ct10:cvr: dmi.product.name: HP Licrice dmi.product.version: A3009CD10002 dmi.sys.vendor: Hewlett-Packard To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1409625/+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