Comment 0 for bug 1750513

On 4.13 kernels I cannot change brightness of my display. Other users of the same laptop model also have the issue. Using kernel 4.10 the problem doesn't happen and brightness can be changed using hardware buttons(fn+f5, fn+f6). On 4.13 I cannot find any settings that would allow me to change brightness.
On 4.13 linux always starts with really dimmed screen which makes the computer hard to use in any kind of daylight, even indoors.

lsb_release -rd:
Description: Ubuntu 16.04.3 LTS
Release: 16.04

uname -a:
Linux redacted-ThinkPad-P51 4.13.0-32-generic #35~16.04.1-Ubuntu SMP Thu Jan 25 10:13:43 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
(also happens in any earlier version of 4.13, I need to revert up to 4.10 in order for it to work)

Hardware:
Lenovo ThinkPad P51 15.6"

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.13.0-32-generic 4.13.0-32.35~16.04.1
ProcVersionSignature: Ubuntu 4.13.0-32.35~16.04.1-generic 4.13.13
Uname: Linux 4.13.0-32-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Feb 20 09:00:09 2018
InstallationDate: Installed on 2017-10-03 (139 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
SourcePackage: linux-hwe
UpgradeStatus: No upgrade log present (probably fresh install)