Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.17 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'. 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/v4.17 ** Package changed: linux-signed (Ubuntu) => linux (Ubuntu) ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Tags added: kernel-da-key -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-signed in Ubuntu. https://bugs.launchpad.net/bugs/1775065 Title: No brightness controls and /sys/class/backlight empty after upgrade to Bionic on laptop with GeForce GTX 1060 Mobile (kernel parameter acpi_osi= is a workaround) Status in linux package in Ubuntu: New Bug description: This is a case of "Backlight control does not work, and there are no entries in /sys/class/backlight" for what lspci reports as "NVIDIA Corporation GP106M [GeForce GTX 1060 Mobile] (rev a1)" where the kernel parameter acpi_osi= is a workaround. (The workaround is also recorded on Ask Ubuntu at https://askubuntu.com/questions/1030526 /brightness-on-laptop-msi-gt72vr-in-ubuntu-18-04-with-nvidia-gtx-1060 -mobile-does/1043598#1043598.) The problem is new for me after upgrade to Bionic, although the cause might be the corresponding update to the NVIDIA drivers. I will add attachments following the instructions at https://wiki.ubuntu.com/Kernel/Debugging/Backlight, though most of them seem to be uninteresting. If I can provide further information, please let me know. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-22-generic 4.15.0-22.24 ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17 Uname: Linux 4.15.0-22-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.9-0ubuntu7.1 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Jun 4 14:20:34 2018 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed UpgradeStatus: Upgraded to bionic on 2018-06-04 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1775065/+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