brightness level not remembered on HP ZBook 15

Anytime I boot up the system, it always sets the display brightness to 100%.

I can reduce the brighness using the Fn F9 key stroke. Similarly I can increase the brighntess using the Fn F10 combination. (This did not work until recently - see my bug report 1257766). However, even now the chosen value is not remembered. After each start of the system I have to set a convenient brightness level.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xserver-xorg-video-intel 2:2.99.910-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Thu Apr 24 18:53:45 2014
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation 4th Gen Core Processor Integrated Graphics Controller [8086:0416] (rev 06) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:1909]
 NVIDIA Corporation GK107GLM [Quadro K1100M] [10de:0ff6] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:1909]
InstallationDate: Installed on 2014-01-31 (83 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140130)
MachineType: Hewlett-Packard HP ZBook 15
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic root=UUID=56c3d081-90f2-445f-ade1-574586237cd6 ro quiet splash vt.handoff=7
SourcePackage: xserver-xorg-video-intel
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/25/2013
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: L70 Ver. 01.06
dmi.board.name: 1909
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 94.47
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvrL70Ver.01.06:bd10/25/2013:svnHewlett-Packard:pnHPZBook15:pvrA3009DD10303:rvnHewlett-Packard:rn1909:rvrKBCVersion94.47:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP ZBook 15
dmi.product.version: A3009DD10303
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.11+14.04.20140409-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.52-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.0-4ubuntu5
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.0-4ubuntu5
version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
xserver.bootTime: Thu Apr 24 18:40:23 2014
xserver.configfile: default
xserver.errors:
 Failed to load module "nvidia" (module does not exist, 0)
 Failed to load module "nvidia" (module does not exist, 0)
 NOUVEAU(G0): [XvMC] Failed to initialize extension.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 4589
 vendor AUO
xserver.version: 2:1.15.1-0ubuntu2