LCD backlight brighness reset to maximum after boot / resume / login

[Piotr Kołaczkowski]

The laptop LCD backlight brightness level is not preserved. The screen brightness always gets reset to 2-steps below the maximum level after login or resume from suspend. This is particularly annoying when working on battery, because after each resume, I have to make screen darker in order to preserve energy.

It is possible to control brightness by keyboard buttons and by status-bar slider, so brightness control mostly works. The status-bar slider behaves a bit erratically when moved, but not sure if it is related.

The problem seems to be not related to kernel version.
The problem existed in 18.04 as well as 18.10.

Hardware: Dell Precision 5520.
Graphics driver: Intel, using integrated GPU.
Nvidia card turned off on boot, no proprietary Nvidia drivers loaded.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: gnome-shell 3.30.1-2ubuntu1
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 14 14:25:37 2018
DisplayManager: gdm3
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-xenial-amd64-20160624-2
InstallationDate: Installed on 2017-04-12 (549 days ago)
InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.