Meanwhile after some updates I manage to login even without power supply. After that the screen is distorted and looks like this - s. attachment. In the screen you see right a shadow - my taskbar. You can only see the top bar of windows.
** Attachment added: "IMG_20200414_230842.jpg" https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amdgpu/+bug/1872452/+attachment/5354178/+files/IMG_20200414_230842.jpg -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xserver-xorg-video-amdgpu in Ubuntu. https://bugs.launchpad.net/bugs/1872452 Title: [amdgpu] Boot into black screen without power supply (Kubuntu on AMD / Thinkpad T495) Status in kwin package in Ubuntu: New Status in xserver-xorg-video-amdgpu package in Ubuntu: New Bug description: Always when I turn on my Lenovo Thinkpad T495 (AMD CPU)- without the power supply connected - the laptop boots correctly at the beginning, but then just before going to the login screen it gets black. It can only be restarted. When I attach the power supply before the laptop boot everything works correctly. I see this behavior only on Kubuntu (with KDE desktop). On Ubuntu 20.04 everything works fine. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: xorg 1:7.7+19ubuntu14 ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27 Uname: Linux 5.4.0-21-generic x86_64 ApportVersion: 2.20.11-0ubuntu26 Architecture: amd64 BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log' CasperMD5CheckResult: skip CompositorRunning: None CurrentDesktop: KDE Date: Mon Apr 13 14:20:17 2020 DistUpgraded: Fresh install DistroCodename: focal DistroVariant: ubuntu ExtraDebuggingInterest: I just need to know a workaround GraphicsCard: Advanced Micro Devices, Inc. [AMD/ATI] Picasso [1002:15d8] (rev d2) (prog-if 00 [VGA controller]) Subsystem: Lenovo Picasso [17aa:5125] InstallationDate: Installed on 2020-04-02 (10 days ago) InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Beta amd64 (20200401) MachineType: LENOVO 20NKS01Y00 ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-21-generic root=UUID=d6957960-70a9-45a8-98b1-b0a14d07b829 ro quiet splash vt.handoff=7 SourcePackage: xorg Symptom: display UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/28/2019 dmi.bios.vendor: LENOVO dmi.bios.version: R12ET46W(1.16 ) dmi.board.asset.tag: Not Available dmi.board.name: 20NKS01Y00 dmi.board.vendor: LENOVO dmi.board.version: Not Defined dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrR12ET46W(1.16):bd10/28/2019:svnLENOVO:pn20NKS01Y00:pvrThinkPadT495:rvnLENOVO:rn20NKS01Y00:rvrNotDefined:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad T495 dmi.product.name: 20NKS01Y00 dmi.product.sku: LENOVO_MT_20NK_BU_Think_FM_ThinkPad T495 dmi.product.version: ThinkPad T495 dmi.sys.vendor: LENOVO version.compiz: compiz N/A version.libdrm2: libdrm2 2.4.101-1 version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-1ubuntu1 version.libgl1-mesa-glx: libgl1-mesa-glx N/A version.xserver-xorg-core: xserver-xorg-core 2:1.20.7-2ubuntu2 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+git20190815-1 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/kwin/+bug/1872452/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp