** Tags added: kernel-bug-exists-upstream -- 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/1685620
Title: Screen flashes continuously when brightness set to lower than 100% using fn keys on Samsung NT200B5C-STW/R laptop running Lubuntu 17.04 x64 Status in linux package in Ubuntu: Incomplete Bug description: Followed instructions here: https://wiki.ubuntu.com/Kernel/Debugging/Backlight Category: Backlight control does not work, but there are entries in /sys/class/backlight System: Samsung NT200B5C-STW/R notebook, Lubuntu 17.04 x64 More info: - Dimming the screen in the BIOS using the function keys works as expected, so doesn't appear to be a hardware issue. - After installing Lubuntu 17.04 x64, the screen is at full brightness. - Attempting to dim the screen using the function keys does not work. However the brightness applet is displayed and /sys/class/backlight/intel_backlight/brightness file is modified. However, at lower settings, instead of dimming, the backlight appears to switch on and off continuously. If the brightness is set back up to 100%, the flashing ceases. The on off cycling appears to increase in frequency the lower the brightness setting. - Ran all debugging info commands. Note that dsdt.dat is lowercase. See backlight.zip (attached as one zip as the site isn't allowing multiple attachments for some reason) - Setting acpi_backlight=vendor ... No change - /sys/class/backlight/intel_backlight/brightness is present. ... Changing the number has the same effect as using the Fn keys. Values lower than 100% cause the screen to cycle on and off continuously. - Kernel param: video.use_bios_initial_backlight=0 ... same behavior. - Kernal param: acpi_osi= ... same behavior - Kernel version is: 4.10.0-19-generic - Kernel param: acpi.brightness_switch_enabled=0 ... same behavior - $ dmesg | grep 'ACPI: Video' [ 2.481461] ACPI: Video Device [PEGP] (multi-head: yes rom: yes post: no) [ 2.482043] ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no) - $ lspci |grep VGA 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) ProblemType: Bug DistroRelease: Ubuntu 17.04 Package: linux-image-4.10.0-19-generic 4.10.0-19.21 [modified: boot/vmlinuz-4.10.0-19-generic] ProcVersionSignature: Ubuntu 4.10.0-19.21-generic 4.10.8 Uname: Linux 4.10.0-19-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.10.0-19-generic. ApportVersion: 2.20.4-0ubuntu4 Architecture: amd64 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: flgc 1174 F.... pulseaudio Card0.Amixer.info: Card hw:0 'PCH'/'HDA Intel PCH at 0xf7e30000 irq 34' Mixer name : 'Realtek ALC269VC' Components : 'HDA:10ec0269,144dc0e4,00100202 HDA:80862806,80860101,00100000' Controls : 28 Simple ctrls : 11 CurrentDesktop: LXDE Date: Sun Apr 23 20:10:20 2017 HibernationDevice: RESUME=UUID=145d228c-4542-4aab-901e-894d929d2085 InstallationDate: Installed on 2017-04-23 (0 days ago) InstallationMedia: Lubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412) MachineType: SAMSUNG ELECTRONICS CO., LTD. 400B4C/400B5C/200B4C/200B5C ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.10.0-19-generic.efi.signed root=UUID=3312063b-5d45-48b3-9e73-34065c10b162 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.10.0-19-generic N/A linux-backports-modules-4.10.0-19-generic N/A linux-firmware 1.164 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/14/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P05AAZ.033.130814.dg dmi.board.asset.tag: No Asset Tag dmi.board.name: SAMSUNG_NP1234567890 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.:bvrP05AAZ.033.130814.dg:bd08/14/2013:svnSAMSUNGELECTRONICSCO.,LTD.:pn400B4C/400B5C/200B4C/200B5C:pvrP05AAZ:rvnSAMSUNGELECTRONICSCO.,LTD.:rnSAMSUNG_NP1234567890:rvrSEC_SW_REVISION_1234567890ABCD:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvrN/A: dmi.product.name: 400B4C/400B5C/200B4C/200B5C dmi.product.version: P05AAZ dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1685620/+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
