In 4.15.0-25-generic, the symptoms have changed. The objectionable temporal dithering persists in virtual terminals (e.g. Ctrl+Alt+F1) but under KDE Plasma 5 it has disappeared or become imperceptible, and high fps video playback is no longer choppy.
However, with this kernel, the blurring effect applied to semi- transparent Plasma widget backgrounds has stopped working (replaced with opaque background). -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1776642 Title: Temporal dithering and impaired graphical performance started appearing on Intel HD 530 graphics Status in linux package in Ubuntu: Confirmed Bug description: I am experiencing a regression in linux-image-generic-hwe-16.04 with Intel HD Graphics 530 (Core i5-6600T), starting in 4.13.0-43 (considering only kernels which appear in my GRUB menu). Some form of spatio-temporal dithering has been enabled. This is causing a shimmering effect and visible dithering patterns (like woven textile) which are noticeable on photographs and areas of similar colour. 1px borders in the UI can appear to have a "marching ants" effect. The effect is visible both under Xorg and in a virtual console (Ctrl+Alt+F1), if the displayed colours are suitable to trigger it. Booting 4.13.0-41 eliminates the temporal dithering. This occurs on a (presumed) 6bpp laptop LCD panel, so dithering is necessary, but in previous kernels only a form of spatial dithering is applied, which is less visually obvious. Concurrent with the temporal dithering, I have also noticed general poor graphical performance with the affected kernels. E.g. 50fps and 60fps video playback is choppy, sometimes slow redraw and other graphical glitches on UI elements. Like the temporal dithering, these additional problems disappear if I revert to 4.13.0-41. --- ApportVersion: 2.20.1-0ubuntu2.18 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: patrick 1976 F.... pulseaudio DistroRelease: Ubuntu 16.04 EcryptfsInUse: Yes HibernationDevice: RESUME=UUID=72e179a8-b27c-42d3-9523-8f1cceacaa64 InstallationDate: Installed on 2016-09-16 (634 days ago) InstallationMedia: Kubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) MachineType: PC Specialist Limited N350DW Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-45-generic root=UUID=deeef076-c1e1-47ec-8ee4-d3b56fa179f9 ro quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 4.13.0-45.50~16.04.1-generic 4.13.16 RelatedPackageVersions: linux-restricted-modules-4.13.0-45-generic N/A linux-backports-modules-4.13.0-45-generic N/A linux-firmware 1.157.19 Tags: xenial xenial Uname: Linux 4.13.0-45-generic x86_64 UnreportableReason: The report belongs to a package that is not installed. UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lp lpadmin plugdev sambashare sudo vboxusers _MarkForUpload: False dmi.bios.date: 05/26/2016 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 5.11 dmi.board.asset.tag: Tag 12345 dmi.board.name: N350DW dmi.board.vendor: CLEVO dmi.board.version: Not Applicable dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: No Enclosure dmi.chassis.version: N/A dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr5.11:bd05/26/2016:svnPCSpecialistLimited:pnN350DW:pvrNotApplicable:rvnCLEVO:rnN350DW:rvrNotApplicable:cvnNoEnclosure:ct10:cvrN/A: dmi.product.family: Not Applicable dmi.product.name: N350DW dmi.product.version: Not Applicable dmi.sys.vendor: PC Specialist Limited To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1776642/+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
