Internal laptop display defaults to low refresh rate

[Jan Praczyk]

It appears that ever since kernel ~4.14, there was a bug in i915 DRM that caused the internal laptop displays connected by eDP to default to 40 Hz screen refresh rate.

Affected Ubuntu release: 18.04
Kernel package version: 4.15.0-22.24
What you expected to happen: The refresh rate has a sane default setting
What happened instead: The refresh rate defaults to 40 Hz
Upstream bug report: https://bugs.freedesktop.org/show_bug.cgi?id=103497
This has already been fixed in drm-tip: https://cgit.freedesktop.org/drm-tip/commit/?id=d93fa1b47b8fcd149b5091f18385304f402a8e15

I do confirm that the latest daily build cod/tip/drm-tip/2018-06-03 (8fdb62e0511e81fa935059c274a2457361fdb679) of drm-tip kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-tip/current/ indeed fixes this issue for me.

Known workarounds: The user can force the display to use other refresh rates close to 60 Hz (59,96 works quite well in my case)

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-22-generic 4.15.0-22.24
Uname: Linux 4.17.0-994-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Jun 3 16:53:20 2018
InstallationDate: Installed on 2018-06-03 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-signed
UpgradeStatus: No upgrade log present (probably fresh install)