I can confirm this very same problem in my laptop, which is a Thinkpad P1 with a Xeon E-2176M and hybrid Intel / NVIDIA card working in "Discreet" mode (that is, only the NVIDIA card is enabled) using the proprietary NVIDIA driver installed via the nvidia-driver-390 package (390.87-0ubuntu1).
The NVIDIA card is a Quadro P2000 Mobile according to lspci: 01:00.0 VGA compatible controller: NVIDIA Corporation GP107GLM [Quadro P2000 Mobile] (rev a1) I'm currently in Ubuntu 18.10 Cosmic Cuttlefish with kernel 4.18.0-10: $ cat /etc/os-release NAME="Ubuntu" VERSION="18.10 (Cosmic Cuttlefish)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 18.10" VERSION_ID="18.10" HOME_URL="https://www.ubuntu.com/"; SUPPORT_URL="https://help.ubuntu.com/"; BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"; PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"; VERSION_CODENAME=cosmic UBUNTU_CODENAME=cosmic $ uname -ar Linux rosmon 4.18.0-10-generic #11-Ubuntu SMP Thu Oct 11 15:13:55 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux And just to confirm, what I'm seeing is this: 1. Pressing the media keys for brightness cause not visible effect (no brightness change), with errors showing up in the journal: oct 23 11:37:47 rosmon gsd-media-keys[2532]: Failed to set new screen percentage: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available oct 23 11:37:47 rosmon gsd-media-keys[2532]: Failed to set new screen percentage: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available 2. Installing xbacklight allows me to effectively change the brightness from the command line (e.g. `xbacklight -set 50`, `xbacklight -inc 10`...) 3. The /sys/class/backlight directory is empty, suggesting that the ACPI interface was not initialize, which I believe is why the media keys don't work and throw that error in the journal (media keys -> gsd-media- keys -> gsd-power-manager -> GUDev -> /sys/class/backlight ACPI interface): $ ls -l /sys/class/backlight/ total 0 4. Booting with acpi_osi= or acpi_osi=Linux causes the /sys/class/backlight directory to be populated with a thinkpad_backlight directory, and the media keys to respond showing the OSD for the brightness, but does not change brightness at all when used: a. The brightness bar is always shown at "random" values between 0 and ~20% b. /sys/class/backlight/thinkpad_backlight/actual_brightness is always 0 Also, in this setup where /sys/class/backlight/ is not empty, xbacklight does NOT work. I hope this is helpful, as it's kind of annoying to have to use xbacklight to change brithgness. I was myself looking into a fix for this, but I can't figure out whether this should be fixed in the NVIDIA driver, some kernel module or somewhere else, so I figured I'd comment here and hope for the best. PS: I can do more tests if needed. Thanks! -- 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/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: Confirmed 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) --- ApportVersion: 2.20.9-0ubuntu7.1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: bgarvin 2442 F.... pulseaudio /dev/snd/controlC0: bgarvin 2442 F.... pulseaudio CurrentDesktop: ubuntu:GNOME DistroRelease: Ubuntu 18.04 HibernationDevice: RESUME=UUID=1b60cccb-eea7-4d0b-a32b-97d236a5177f Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 004: ID 04f2:b5a7 Chicony Electronics Co., Ltd Bus 001 Device 003: ID 8087:0a2b Intel Corp. Bus 001 Device 002: ID 1c7a:0603 LighTuning Technology Inc. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: System76, Inc. Oryx Pro NonfreeKernelModules: nvidia_modeset nvidia 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 EFI VGA ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-22-generic root=UUID=557ebdfc-3380-4721-a494-65c34cb70b2f ro i8042.nomux i8042.reset acpi_osi= ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17 RelatedPackageVersions: linux-restricted-modules-4.15.0-22-generic N/A linux-backports-modules-4.15.0-22-generic N/A linux-firmware 1.173.1 Tags: bionic Uname: Linux 4.15.0-22-generic x86_64 UpgradeStatus: Upgraded to bionic on 2018-06-04 (1 days ago) UserGroups: adm lpadmin sambashare sudo vboxusers _MarkForUpload: True dmi.bios.date: 09/08/2016 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 1.05.03RSA dmi.board.asset.tag: Tag 12345 dmi.board.name: Oryx Pro dmi.board.vendor: System76, Inc. dmi.board.version: oryp2 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: System76, Inc. dmi.chassis.version: N/A dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1.05.03RSA:bd09/08/2016:svnSystem76,Inc.:pnOryxPro:pvroryp2:rvnSystem76,Inc.:rnOryxPro:rvroryp2:cvnSystem76,Inc.:ct10:cvrN/A: dmi.product.family: Not Applicable dmi.product.name: Oryx Pro dmi.product.version: oryp2 dmi.sys.vendor: System76, Inc. 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