I upgraded my kernel to 5.6.0-1020-oem in order to test. The issue is better then, but not resolved. When using the lock screen one out of the two monitors is lost.
This errors are in dmesg: [257474.965612] [drm:intel_dp_link_training_clock_recovery [i915]] *ERROR* failed to get link status [257474.974761] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun -- 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/1889342 Title: Thunderbolt Dock Loses Monitors Status in linux package in Ubuntu: Confirmed Bug description: After a suspend or locking the only way to regain external monitors is to unplug and replug the thunderbolt dock back in. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-42-generic 5.4.0-42.46 ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44 Uname: Linux 5.4.0-42-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.4 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: john 2682 F.... pulseaudio /dev/snd/controlC0: john 2682 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Wed Jul 29 00:22:26 2020 DistributionChannelDescriptor: # This is the distribution channel descriptor for the OEM CDs # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-focal-amd64-20200502-85 InstallationDate: Installed on 2020-07-13 (15 days ago) InstallationMedia: Ubuntu 20.04 "Focal" - Build amd64 LIVE Binary 20200502-05:58 MachineType: Dell Inc. XPS 13 9300 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-42-generic root=UUID=5e141eb0-e03b-4c39-b826-f94e0d2715ea ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-42-generic N/A linux-backports-modules-5.4.0-42-generic N/A linux-firmware 1.187.2 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 05/08/2020 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.0.11 dmi.board.name: 0WX9VX dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.0.11:bd05/08/2020:svnDellInc.:pnXPS139300:pvr:rvnDellInc.:rn0WX9VX:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.family: XPS dmi.product.name: XPS 13 9300 dmi.product.sku: 096D dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1889342/+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
