You have been subscribed to a public bug: None of the boot parameters worked, but with acpi_backlight=vendor the backlight was dimmer (systemd-backlight didn't fail). The only way it starts working is to do "setpci -v -H1 -s 00:01.00 BRIDGE_CONTROL=0"
ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-45-generic 5.4.0-45.49 ProcVersionSignature: Ubuntu 5.4.0-45.49-generic 5.4.55 Uname: Linux 5.4.0-45-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia wl ApportVersion: 2.20.11-0ubuntu27.8 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: xma 1345 F.... pulseaudio /dev/snd/controlC0: xma 1345 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Tue Sep 1 14:36:14 2020 InstallationDate: Installed on 2020-08-30 (1 days ago) InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731) MachineType: Apple Inc. MacBookPro11,3 ProcFB: 0 EFI VGA ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-45-generic root=UUID=01482a85-82e8-44ce-a63d-a429cd6d5381 ro acpi_osi= RelatedPackageVersions: linux-restricted-modules-5.4.0-45-generic N/A linux-backports-modules-5.4.0-45-generic N/A linux-firmware 1.187.3 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 06/10/2020 dmi.bios.vendor: Apple Inc. dmi.bios.version: 162.0.0.0.0 dmi.board.asset.tag: Base Board Asset Tag# dmi.board.name: Mac-2BD1B31983FE1663 dmi.board.vendor: Apple Inc. dmi.board.version: MacBookPro11,3 dmi.chassis.type: 10 dmi.chassis.vendor: Apple Inc. dmi.chassis.version: Mac-2BD1B31983FE1663 dmi.modalias: dmi:bvnAppleInc.:bvr162.0.0.0.0:bd06/10/2020:svnAppleInc.:pnMacBookPro11,3:pvr1.0:rvnAppleInc.:rnMac-2BD1B31983FE1663:rvrMacBookPro11,3:cvnAppleInc.:ct10:cvrMac-2BD1B31983FE1663: dmi.product.family: Mac dmi.product.name: MacBookPro11,3 dmi.product.sku: System SKU# dmi.product.version: 1.0 dmi.sys.vendor: Apple Inc. ** Affects: nvidia-graphics-drivers (Ubuntu) Importance: Undecided Status: Confirmed ** Tags: amd64 apport-bug focal -- [Ubuntu 20.04.1 LTS] Backlight brightness can't be changed, even in /sys/ https://bugs.launchpad.net/bugs/1893795 You received this bug notification because you are a member of Ubuntu-X, which is subscribed to nvidia-graphics-drivers in Ubuntu. _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp