brightness keys are not working.

[pruthvi]

I am using Dell xps-l501x and i recently upgraded my ubuntu to 14.04.
when i press f5, the brightness increases and when i press f5 to decrease, it reaches maximum.
In the touch panel which has 3 buttons, the middle button performs the action which was supposed to be the function of f4 !!
please help me debug this problem as i am new to the ubuntu world.
Thank you :)

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-32-generic 3.13.0-32.56
ProcVersionSignature: Ubuntu 3.13.0-32.56-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: pruthvi 2464 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Jul 10 20:35:13 2014
InstallationDate: Installed on 2014-02-21 (138 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Dell Inc. XPS L501X
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-32-generic root=UUID=0bd76ea8-c534-46c2-b398-603109807bee ro GRUB_CMDLINE_LINUX_DEFAULT=quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-32-generic N/A
 linux-backports-modules-3.13.0-32-generic N/A
 linux-firmware 1.127.4
SourcePackage: linux
UpgradeStatus: Upgraded to trusty on 2014-07-08 (1 days ago)
dmi.bios.date: 03/29/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A07
dmi.board.vendor: Dell Inc.
dmi.board.version: A07
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A07
dmi.modalias: dmi:bvnDellInc.:bvrA07:bd03/29/2011:svnDellInc.:pnXPSL501X:pvrA07:rvnDellInc.:rn:rvrA07:cvnDellInc.:ct8:cvrA07:
dmi.product.name: XPS L501X
dmi.product.version: A07
dmi.sys.vendor: Dell Inc.

[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 v3.16 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/v3.16-rc4-utopic/

[Launchpad Janitor (janitor)]

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