Public bug reported: Backlight control does not work, but there are entries in /sys/class/backlight.
Laptop model is: NP530U4E-K10RU Video adapter: Intel HD graphics 4000 I've tried all the suggestions from https://wiki.ubuntu.com/Kernel/Debugging/Backlight kernel parameters acpi_backlight=vendor, video.use_bios_initial_backlight=0, video.use_native_backlight=1 didn't work. In this laptop brightness is controlled by Fn + F2 and Fn+F3. Whenever i try to change brightness, the value in /sys/class/backlight/intel_backlight/brightness changes, but actual screen brightness is the same. All the logs are in the attached archive. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: linux-image-4.2.0-25-generic 4.2.0-25.30 ProcVersionSignature: Ubuntu 4.2.0-25.30-generic 4.2.6 Uname: Linux 4.2.0-25-generic x86_64 ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: Unity Date: Sat Jan 23 09:55:32 2016 HibernationDevice: RESUME=UUID=9d4a6619-c5f9-46c2-b11b-e230e9d357e3 InstallationDate: Installed on 2014-05-20 (613 days ago) InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1) MachineType: SAMSUNG ELECTRONICS CO., LTD. 530U4E/540U4E ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-25-generic root=UUID=686fa320-83d1-4015-a632-bb2a91390ab6 ro quiet splash video.use_bios_initial_backlight=0 vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.2.0-25-generic N/A linux-backports-modules-4.2.0-25-generic N/A linux-firmware 1.149.3 SourcePackage: linux UpgradeStatus: Upgraded to wily on 2015-11-25 (58 days ago) dmi.bios.date: 02/26/2014 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P08ACM.065.140226.dg dmi.board.asset.tag: No Asset Tag dmi.board.name: NP530U4E-K01RU 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.:bvrP08ACM.065.140226.dg:bd02/26/2014:svnSAMSUNGELECTRONICSCO.,LTD.:pn530U4E/540U4E:pvrP08ACM:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP530U4E-K01RU:rvrSEC_SW_REVISION_1234567890ABCD:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvrN/A: dmi.product.name: 530U4E/540U4E dmi.product.version: P08ACM dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD. ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug wily ** Attachment added: "backlight_bug_report.tar.gz" https://bugs.launchpad.net/bugs/1537324/+attachment/4555228/+files/backlight_bug_report.tar.gz -- 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/1537324 Title: No brightness control on Samsung NP530U4E-K10RU Status in linux package in Ubuntu: New Bug description: Backlight control does not work, but there are entries in /sys/class/backlight. Laptop model is: NP530U4E-K10RU Video adapter: Intel HD graphics 4000 I've tried all the suggestions from https://wiki.ubuntu.com/Kernel/Debugging/Backlight kernel parameters acpi_backlight=vendor, video.use_bios_initial_backlight=0, video.use_native_backlight=1 didn't work. In this laptop brightness is controlled by Fn + F2 and Fn+F3. Whenever i try to change brightness, the value in /sys/class/backlight/intel_backlight/brightness changes, but actual screen brightness is the same. All the logs are in the attached archive. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: linux-image-4.2.0-25-generic 4.2.0-25.30 ProcVersionSignature: Ubuntu 4.2.0-25.30-generic 4.2.6 Uname: Linux 4.2.0-25-generic x86_64 ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: Unity Date: Sat Jan 23 09:55:32 2016 HibernationDevice: RESUME=UUID=9d4a6619-c5f9-46c2-b11b-e230e9d357e3 InstallationDate: Installed on 2014-05-20 (613 days ago) InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1) MachineType: SAMSUNG ELECTRONICS CO., LTD. 530U4E/540U4E ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-25-generic root=UUID=686fa320-83d1-4015-a632-bb2a91390ab6 ro quiet splash video.use_bios_initial_backlight=0 vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.2.0-25-generic N/A linux-backports-modules-4.2.0-25-generic N/A linux-firmware 1.149.3 SourcePackage: linux UpgradeStatus: Upgraded to wily on 2015-11-25 (58 days ago) dmi.bios.date: 02/26/2014 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P08ACM.065.140226.dg dmi.board.asset.tag: No Asset Tag dmi.board.name: NP530U4E-K01RU 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.:bvrP08ACM.065.140226.dg:bd02/26/2014:svnSAMSUNGELECTRONICSCO.,LTD.:pn530U4E/540U4E:pvrP08ACM:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP530U4E-K01RU:rvrSEC_SW_REVISION_1234567890ABCD:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvrN/A: dmi.product.name: 530U4E/540U4E dmi.product.version: P08ACM dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD. 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