> 1. the grep . /var/lib/systemd/backlight/* shows the value of the brightness that was right before the last reboot. That doesn't change real-time when I change the brightness with the slider. The value appear to get stored right before the reboot.
Yes, the service will restore brightness value at boot, and store brightness value at shutdown stage. It does not save the brightness at realtime. > 2. the cat /sys/class/backlight/intel_backlight/brightness shows whatever is the current value of the brigtness and is stored/updated real-time, as soon as I change it with the slider or the hardware key Yes. that's correct. Systemd saves the brightness before shutdown, then restore it after boot. It doesn't save brightness in real-time. So, wrt comment #20, did you change brightness in anyway? -- 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/1686268 Title: Backlight brightness level not restored after reboot Status in linux package in Ubuntu: Incomplete Bug description: I am not sure if this is the right place to report this, so feel free to move it elsewhere. It looks like the systemd-backlight service (/lib/systemd/system /systemd-backlight@.service) does not restore the brightness level (although it saves it before shut-down). However the following command does restore the saved brightness: sudo /lib/systemd/systemd-backlight load backlight:intel_backlight As a temporary solution to automate it at boot I am using the following line added to the root cron: @reboot /lib/systemd/systemd-backlight load backlight:intel_backlight - Ubuntu 4.10.0-20.22-generic 4.10.8 - Gnome 3.24 Please, let me know if you need more info. Thanks. --- ApportVersion: 2.20.4-0ubuntu4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: dd 1540 F.... pulseaudio CurrentDesktop: GNOME DistroRelease: Ubuntu 17.04 InstallationDate: Installed on 2017-04-12 (13 days ago) InstallationMedia: Ubuntu-GNOME 17.04 "Zesty Zapus" - Release amd64 (20170411) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0a2b Intel Corp. Bus 001 Device 003: ID 1bcf:2b95 Sunplus Innovation Technology Inc. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: Dell Inc. Precision 5520 Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.10.0-20-generic.efi.signed root=/dev/mapper/nvme-ubuntu_gnome ro systemd.restore_state=1 quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 4.10.0-20.22-generic 4.10.8 RelatedPackageVersions: linux-restricted-modules-4.10.0-20-generic N/A linux-backports-modules-4.10.0-20-generic N/A linux-firmware 1.164 Tags: zesty Uname: Linux 4.10.0-20-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip input lpadmin plugdev sambashare sudo _MarkForUpload: True dmi.bios.date: 03/29/2017 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.2.4 dmi.board.name: 06X96V dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.2.4:bd03/29/2017:svnDellInc.:pnPrecision5520:pvr:rvnDellInc.:rn06X96V:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.name: Precision 5520 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1686268/+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
