This is a small piece of the log when watching a log. the i915 eDP driver receives a "hotplug event received", which corresponds with a slingle flickering of the screen. So I assume something goes wrong with retraining the link, or for some reason the screen thinks that the pc is disconnected and triggers an interrupt, which then for some other reason flickers the screen.
I'm not well-versed with eDP 1.4, so I assume to be totally wrong. ** Attachment added: "relevant portion of dmesg with "drm.debug=14" kernel parameter" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875649/+attachment/5362494/+files/dmesg.txt -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1875649 Title: Screen flickering in Kubuntu 20.04 on Lenovo Yoga C940 14-IIL Status in xorg package in Ubuntu: New Bug description: Screen flickering in Kubuntu 20.04 on Lenovo Yoga C940 14-IIL I am filing this bug again in accordance with: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875073/comments/3 I've deleted the repository and checked again, and the bug still persists. Old bug report: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875073 My screen flickers on Kubuntu 20.04LTS. See: https://imgur.com/a/FoWI1sp Also affected: Kubuntu 19.10 Fedora 31 System: inxi -Gxxx Graphics: Device-1: Intel Iris Plus Graphics G7 vendor: Lenovo driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:8a52 Display: x11 server: X.Org 1.20.8 driver: modesetting compositor: kwin_x11 resolution: 1920x1080~60Hz OpenGL: renderer: Mesa Intel Iris Plus Graphics (ICL GT2) v: 4.6 Mesa 20.0.4 direct render: Yes Reproduction scenario's: 1) Starting Kubuntu, screen flickers a couple of times during startup and turns black for multiple seconds. 2) Start a youtube video, near-constant flickering. Audio works fine. 3) Open up various applications. Screen starts flickering every now and then. 4) Leave pc unattended for a long time, screen starts flickering sporadically. Things I tried: * Use various kernels * linux kernel 3.4, 3.5, 3.6, 3.7rc2 * Ubuntu port of linux kernel 3.4.0-26-generic + patch https://gitlab.freedesktop.org/jkrzyszt/i915/-/commit/1ee48a61aa57dbdbc3cd2808d8b28df40d938e44 * intel-drm-next (kernel panic) * Oibaf PPA * various kernel parameters What does work: * When using windows, the screen works. So no hardware error. * When using "nomodeset" kernel parameter Kubuntu 20.04 works, but then there's no sound or hardware acceleration. What I think is happening: i915 is apperantly an unstable driver for eDP 1.4 screens. That, in combination with a 10'th gen intel cpu is not a good combination. According to dmesg the firmware of sof-audio-pci is restarting. [ 324.775087] sof-audio-pci 0000:00:1f.3: error: no reply expected, received 0x0 [ 324.866267] sof-audio-pci 0000:00:1f.3: firmware boot complete Could the audio part of the eDP connection be breaking because of an issue similar to the patch that is mentioned earlyer? ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: xorg 1:7.7+19ubuntu14 ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30 Uname: Linux 5.4.0-26-generic x86_64 ApportVersion: 2.20.11-0ubuntu27 Architecture: amd64 CasperMD5CheckResult: skip CompositorRunning: None Date: Tue Apr 28 15:31:27 2020 DistUpgraded: Fresh install DistroCodename: focal DistroVariant: ubuntu GraphicsCard: Intel Corporation Iris Plus Graphics G7 [8086:8a52] (rev 07) (prog-if 00 [VGA controller]) Subsystem: Lenovo Iris Plus Graphics G7 [17aa:3801] InstallationDate: Installed on 2020-04-25 (3 days ago) InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423) MachineType: LENOVO 81Q9 ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-26-generic root=UUID=5d977dfa-1fa5-412b-9d83-644cef18af6e ro rootflags=subvol=@ quiet splash vt.handoff=7 SourcePackage: xorg Symptom: display UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/09/2020 dmi.bios.vendor: LENOVO dmi.bios.version: AUCN54WW dmi.board.asset.tag: NO Asset Tag dmi.board.name: LNVNB161216 dmi.board.vendor: LENOVO dmi.board.version: SDK0J40709 WIN dmi.chassis.asset.tag: NO Asset Tag dmi.chassis.type: 31 dmi.chassis.vendor: LENOVO dmi.chassis.version: Lenovo Yoga C940-14IIL dmi.modalias: dmi:bvnLENOVO:bvrAUCN54WW:bd01/09/2020:svnLENOVO:pn81Q9:pvrLenovoYogaC940-14IIL:rvnLENOVO:rnLNVNB161216:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrLenovoYogaC940-14IIL: dmi.product.family: Yoga C940-14IIL dmi.product.name: 81Q9 dmi.product.sku: LENOVO_MT_81Q9_BU_idea_FM_Yoga C940-14IIL dmi.product.version: Lenovo Yoga C940-14IIL dmi.sys.vendor: LENOVO version.compiz: compiz N/A version.libdrm2: libdrm2 2.4.101-2 version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-2ubuntu1 version.libgl1-mesa-glx: libgl1-mesa-glx N/A version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875649/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
