I have the same issue in Ubuntu 12.04.3. My laptop is Dell Latitude 3540. -- 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/1069357
Title: [Dell Vostro V131] Hardware keys change backlight brightness in much larger increments/steps than expected Status in “linux” package in Ubuntu: Incomplete Bug description: SInce the upgrade to Ubuntu 12.10, hardware keys for regulating backlight brightness (fn+f4, fn+f5) change brightness in large increments, even though much finer control is available both through the Brightness and Lock dialog in Settings and by just setting the value in /sys/class/backlight/acpi_video0/brightness, for example: # echo 1 > /sys/class/backlight/acpi_video0/brightness /sys/class/backlight/acpi_video0/brightness accepts values 0-15, the default step seems to be 3 instead of 1 as expected, and as it was in Ubuntu 12.04. Partial workaround is to disable brightness switch # echo -n 0 > /sys/module/video/parameters/brightness_switch_enabled which cuts the step to 2. Moreover, adding kernel parameters "acpi_osi=Linux acpi_backlight=legacy" allows for even finer control in the Brightness and Lock dialog in Settings (finer than those 16 settings, including completely turning the backlight via the brightness slider) but breaks the hardware keys functionality completely. # lsb_release -rd Description: Ubuntu 12.10 Release: 12.10 --- ApportVersion: 2.6.1-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: rmo 1897 F.... pulseaudio DistroRelease: Ubuntu 12.10 HibernationDevice: RESUME=UUID=7c82e11d-4211-4789-90b6-7a20abd8aa82 InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5) MachineType: Dell Inc. Vostro V131 Package: linux (not installed) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.5.0-17-generic root=/dev/mapper/ubuntu-root ro ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5 RelatedPackageVersions: linux-restricted-modules-3.5.0-17-generic N/A linux-backports-modules-3.5.0-17-generic N/A linux-firmware 1.95 Tags: quantal running-unity Uname: Linux 3.5.0-17-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo dmi.bios.date: 10/24/2011 dmi.bios.vendor: Dell Inc. dmi.bios.version: A03 dmi.board.name: 0X3GJK dmi.board.vendor: Dell Inc. dmi.board.version: A03 dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvrA03:bd10/24/2011:svnDellInc.:pnVostroV131:pvrNotSpecified:rvnDellInc.:rn0X3GJK:rvrA03:cvnDellInc.:ct8:cvrNotSpecified: dmi.product.name: Vostro V131 dmi.product.version: Not Specified dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1069357/+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
