[Regression] Colour banding appears on Lenovo B50-80 integrated display
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Kai-Heng Feng | ||
Bionic |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
The problem affects the integrated display on a Lenovo B50-80 notebook.
Colour banding is visible everywhere on the system, as dithering seems not to be enabled on this 6bpp display. This issue was not present on non-HWE Ubuntu 16.04, and it showed up after I upgraded to Ubuntu 18.04. There was already a very similar bug #1749420 that had a fix released, however, because the make and model of an LCD screen in that case was different, the quirk added to the kernel did not address the problem that affects my machine. The cause of this issue is probably the same, since I have checked that pre-4.8.0-rc2 kernels handled dithering correctly, and 4.8.0-rc2 and later kernels already had the bug described. I believe that adding quirk for an another type of display may fix the problem.
I attached the results of running
sudo get-edid | parse-edid in a file named edid.txt
and
sudo get-edid | edid-decode in a file named edid-decoded.txt.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-
ProcVersionSign
Uname: Linux 4.15.0-32-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
/dev/snd/
Date: Wed Aug 22 00:26:15 2018
HibernationDevice: RESUME=
InstallationDate: Installed on 2018-08-21 (0 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
MachineType: LENOVO 80EW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
PulseList:
Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied
No PulseAudio daemon running, or not running as session daemon.
RelatedPackageV
linux-
linux-
linux-firmware 1.173.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/02/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: A8CN54WW(V3.07)
dmi.board.
dmi.board.name: Lenovo B50-80
dmi.board.vendor: LENOVO
dmi.board.version: 31900058 WIN
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.
dmi.modalias: dmi:bvnLENOVO:
dmi.product.family: IDEAPAD
dmi.product.name: 80EW
dmi.product.
dmi.sys.vendor: LENOVO
description: | updated |
Changed in linux (Ubuntu): | |
status: | Confirmed → Fix Committed |
tags: | added: verification-done-cosmic |
tags: |
added: verification-done-bionic removed: verification-needed-bionic |
Changed in linux (Ubuntu Bionic): | |
status: | New → Fix Committed |
tags: | added: cscc |
tags: |
added: verification-done-xenial removed: verification-needed-xenial |
This change was made by a bot.