Joseph Salisbury, Can you please check the Stefan's comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1399823/comments/8
-- 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/1454207 Title: Samsung 730U3E LCD backlight brightness control doesn't work Status in linux package in Ubuntu: Incomplete Bug description: Fn-shortcuts work and the value in /sys/class/backlight/intel_backlight/brightness changes, but is has no physical effect. Only setting /sys/class/backlight/intel_backlight/brightness to 0 turns the LCD off, changing it to any other value turns it on again. I tried to set different boot parameters in /etc/defaults/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=0" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_bios_initial_backlight=0" For each change, I called update-grub, restarted, and verfied the settings with /proc/cmdline. Nothing worked for me. I also tested this with the newest mainline kernel (4.1-rc2), but the bug still exists. It work with trusty and stopped working with utopic. I thought this issue would may be fixed in vivid, but it isn't. Please tell me what other information you need in order to fix this. ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: linux-image-3.19.0-16-generic 3.19.0-16.16 ProcVersionSignature: Ubuntu 3.19.0-16.16-generic 3.19.3 Uname: Linux 3.19.0-16-generic x86_64 ApportVersion: 2.17.2-0ubuntu1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: stefan 1383 F.... pulseaudio CurrentDesktop: KDE Date: Tue May 12 13:08:51 2015 HibernationDevice: RESUME=UUID=34e06653-f31c-45ef-80ca-9eddcae5134f InstallationDate: Installed on 2015-03-10 (62 days ago) InstallationMedia: Kubuntu-Plasma-5 14.10 "Utopic Unicorn" - Release amd64 (20141022) MachineType: SAMSUNG ELECTRONICS CO., LTD. 730U3E/740U3E ProcFB: 0 inteldrmfb 1 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-16-generic root=/dev/mapper/kubuntu--plasma--5--vg-root ro quiet splash video.use_bios_initial_backlight=0 RelatedPackageVersions: linux-restricted-modules-3.19.0-16-generic N/A linux-backports-modules-3.19.0-16-generic N/A linux-firmware 1.143 SourcePackage: linux UpgradeStatus: Upgraded to vivid on 2015-04-26 (16 days ago) dmi.bios.date: 05/30/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P05ABW.060.130530.dg dmi.board.asset.tag: No Asset Tag dmi.board.name: NP730U3E-S03DE dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD. dmi.board.version: SEC_SW_REVISION_1234567890ABCD dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 9 dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD. dmi.chassis.version: N/A dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP05ABW.060.130530.dg:bd05/30/2013:svnSAMSUNGELECTRONICSCO.,LTD.:pn730U3E/740U3E:pvrP05ABW:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP730U3E-S03DE:rvrSEC_SW_REVISION_1234567890ABCD:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvrN/A: dmi.product.name: 730U3E/740U3E dmi.product.version: P05ABW dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1454207/+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
