Public bug reported: Initial state: backlight brightness is at normal value. Booting to ubuntu, it's still fine. Reboot. Brightness level is set to the lowest possible value. Meanwhile /sys/class/backlight/radeon_bl0/brightness shows 255 as usual. Using keyboard controls or brightness widget fixes it until the next reboot.
The problem appears since 13.04, every release before it including 12.10 and 12.04.2 with kernels up to 3.5.*. Moreover these releases automatically fix the wrong state. Kernels from 3.8 don't work. I couldn't find any kernels between these versions, they are just disappeared from the wild. The problem also appears in other systems released after 2012 including FreeBSD, OpenBSD, Gentoo, CRUX and HaikuOS. Windows 7 works fine. It's probably not the problem with radeon driver because I have the same issue with fglrx or without both. When booting with acpi_backlight=vendor new backlight device named acer-wmi appears. Running the following command changes the actual brightness: echo 8 > /sys/class/backlight/acer-wmi/brightness Booting with video.use_bios_initial_backlight=0 doesn't do anything, brightness controls work fine. Booting with "acpi_osi=" partially fixes the issue: backlight is being restored to the maximal value but not saved on shutdown. Brightness controls work fine but MATE's widget doesn't display the level, only message "No External Display" (acpi_osi=Linux doesn't have this issue). Booting with video.use_native_backlight=1 doesn't change anything, the controls work fine. Files from https://wiki.kubuntu.org/Kernel/Debugging/Backlight are attached (I can't attach more than one file so I had to pack them) ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-59-generic 5.4.0-59.65 ProcVersionSignature: Ubuntu 5.4.0-59.65-generic 5.4.78 Uname: Linux 5.4.0-59-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.14 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: unti1x 1121 F.... pulseaudio /dev/snd/controlC1: unti1x 1121 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: MATE Date: Sat Jan 23 12:26:04 2021 InstallationDate: Installed on 2021-01-04 (18 days ago) InstallationMedia: Ubuntu-MATE 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731) MachineType: Acer Aspire 5742G ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-59-generic root=UUID=b0baea2a-cc5b-4ee6-88e7-cce32fd6d019 ro acpi_osi=Linux quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-59-generic N/A linux-backports-modules-5.4.0-59-generic N/A linux-firmware 1.187.7 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/13/2012 dmi.bios.vendor: Acer dmi.bios.version: V1.30 dmi.board.asset.tag: Base Board Asset Tag dmi.board.name: Aspire 5742G dmi.board.vendor: Acer dmi.board.version: V1.30 dmi.chassis.type: 10 dmi.chassis.vendor: Acer dmi.chassis.version: V1.30 dmi.modalias: dmi:bvnAcer:bvrV1.30:bd08/13/2012:svnAcer:pnAspire5742G:pvrV1.30:rvnAcer:rnAspire5742G:rvrV1.30:cvnAcer:ct10:cvrV1.30: dmi.product.family: Intel_Mobile dmi.product.name: Aspire 5742G dmi.product.sku: Calpella_CRB dmi.product.version: V1.30 dmi.sys.vendor: Acer ** Affects: linux (Ubuntu) Importance: Undecided Status: Confirmed ** Tags: amd64 apport-bug backlight focal radeon ** Attachment added: "report.tar.gz" https://bugs.launchpad.net/bugs/1912887/+attachment/5455951/+files/report.tar.gz -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
