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Title: [Regression] Colour banding appears on Lenovo B50-80 integrated display Status in linux package in Ubuntu: Fix Released 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-4.15.0-32-generic 4.15.0-32.35 ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18 Uname: Linux 4.15.0-32-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: me 1245 F.... pulseaudio /dev/snd/controlC1: me 1245 F.... pulseaudio Date: Wed Aug 22 00:26:15 2018 HibernationDevice: RESUME=UUID=93b28df5-b453-452b-960d-7173994d778e 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=/boot/vmlinuz-4.15.0-32-generic root=UUID=a1cd5b8c-2707-4840-858b-3ca12517193b ro quiet splash vt.handoff=1 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. RelatedPackageVersions: linux-restricted-modules-4.15.0-32-generic N/A linux-backports-modules-4.15.0-32-generic N/A 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.asset.tag: NO Asset Tag dmi.board.name: Lenovo B50-80 dmi.board.vendor: LENOVO dmi.board.version: 31900058 WIN dmi.chassis.asset.tag: NO Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Lenovo B50-80 dmi.modalias: dmi:bvnLENOVO:bvrA8CN54WW(V3.07):bd09/02/2016:svnLENOVO:pn80EW:pvrLenovoB50-80:rvnLENOVO:rnLenovoB50-80:rvr31900058WIN:cvnLENOVO:ct10:cvrLenovoB50-80: dmi.product.family: IDEAPAD dmi.product.name: 80EW dmi.product.version: Lenovo B50-80 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788308/+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
