brightness not change

[amar]

in my laptop Lenovo G510 after change 12.04 to 14.04 brighness not change. Hot keys except volume and mute key i.e. f1 f2 f3 not work. I am new to linux and knows only some command like update upgrade and apt-get install only from various threats. please help me.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-24-generic 3.13.0-24.46 [modified: boot/vmlinuz-3.13.0-24-generic]
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/controlC0: amar 1365 F.... pulseaudio
 /dev/snd/controlC1: amar 1365 F.... pulseaudio
CurrentDesktop: Unity
Date: Sat Feb 28 00:44:38 2015
HibernationDevice: RESUME=UUID=dffabf6d-9ad9-4fd9-9f72-e16b5a16acf6
InstallationDate: Installed on 2015-02-27 (0 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: LENOVO 20238
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-24-generic root=UUID=0110470c-7969-4e0b-b70f-2bc3fa1e09ce ro nomodeset 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
StagingDrivers: rts5139
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/23/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 79CN46WW(V3.05)
dmi.board.asset.tag: No Asset Tag
dmi.board.name: INVALID
dmi.board.vendor: LENOVO
dmi.board.version: 00000000Not Defined
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo G510
dmi.modalias: dmi:bvnLENOVO:bvr79CN46WW(V3.05):bd12/23/2013:svnLENOVO:pn20238:pvrLenovoG510:rvnLENOVO:rnINVALID:rvr00000000NotDefined:cvnLENOVO:ct10:cvrLenovoG510:
dmi.product.name: 20238
dmi.product.version: Lenovo G510
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.0 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.0-rc1-vivid/

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]