Attached is the full kernel log of the most recent failed boot: bootlog-b3-failed.log — kernel log of the failed boot on 2026-10-13 16:13:30 CEST (boot-ID 9f594172c0fd473cabad36ef876d80ac, kernel 7.0.0-38-generic). The panel stayed black for the whole boot; the log contains the DMCUB error flood (~134 "dc_dmub_srv_log_diagnostic_data" messages, ~1/s for ~30 s) plus repeated "kwin_wayland_drm: atomic commit failed: Device or resource busy".
Additional observation: at the end of this failed boot kwin_wayland aborted (SIGABRT) and dumped a core (plasma-kwin_wayland.service, kwin 6.6.6-0ubuntu0.1) — most likely a consequence of the failing DRM commits. Backtrace available on request. Note on the mainline test: I have Secure Boot enabled on this machine, so unsigned mainline kernels will not boot without disabling Secure Boot in the firmware setup first. I will try to get it running in the next couple days. I hope the log helps for now. Ross Porter <[email protected]> schrieb am Mittwoch, 14. Oktober 2026 um 05:35: > Can you get a dmesg or journalctl log from one of the failed boots? > It's also worth testing your `amdgpu.dcdebugmask=0x10` suggestion. > > Can you replicate this on the 7.0 mainline kernel? You can find the > .debs here: https://kernel.ubuntu.com/mainline/ > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/2169805 > > Title: > [7.0.0-38] amdgpu: DMUB/DMCUB errors + intermittent black screen on > boot on Lenovo IdeaPad Slim 3 15AHP10 (HawkPoint1 1002:1900) > > Status in linux package in Ubuntu: > New > > Bug description: > == Summary == > On roughly 20% of power-ons, the laptop boots to a black screen: the panel > stays dark while the system continues running normally (keyboard backlight > on, services start, journal logs normally). Failed boots are accompanied by > a flood of amdgpu DMUB/DMCUB errors. A subsequent reboot always succeeds. > > == System == > - Ubuntu 26.04.1 LTS (resolute), all updates > - Kernel: 7.0.0-38-generic #38-Ubuntu SMP PREEMPT_DYNAMIC > - Desktop: KDE Plasma 6.6.6, Wayland (SDDM) > - Hardware: Lenovo IdeaPad Slim 3 15AHP10 (83KA), BIOS QACN26WW (10/20/2025) > - GPU: AMD HawkPoint1 [1002:1900] (rev c2), driver amdgpu > - linux-firmware-amd-graphics 20260319.git217ca6e4-0ubuntu3.1 > - DMUB firmware: version=0x08005700 (loaded via PSP) > - Kernel cmdline: quiet splash (no amdgpu-specific parameters) > > == Steps to reproduce == > 1. Power the laptop off completely. > 2. Power it on (cold boot). > 3. In roughly 1 of 5 attempts the screen stays black after splash; the > system itself boots fine (verifiable via logs). > > == Expected == > Panel (eDP-1) initializes and the SDDM greeter appears on every boot. > > == Actual == > Black screen. The journal shows the boot proceeding normally, but SDDM/KWin > fails to bring up the display, alongside repeated: > > amdgpu 0000:04:00.0: [drm] *ERROR* Error queueing DMUB command: status=2 > amdgpu 0000:04:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB > error - collecting diagnostic data > kwin_wayland_drm: atomic commit failed: Device or resource busy > workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us > > == Frequency (journalctl statistics, last 46 boots) == > 9 of 46 boots show the DMCUB error flood; almost all of them cold boots. > Example sequence on 2026-10-07 (CEST): > 08:40:47 boot #1: 220 DMCUB errors, no display -> power-cycled > 08:42:38 boot #2: 90 DMCUB errors, no display -> power-cycled > 08:43:29 boot #3: 90 DMCUB errors, no display -> power-cycled > 08:44:32 boot #4: 0 DMCUB errors, boots fine > A warm reboot after a failed attempt virtually always succeeds; the errors > repeat every ~1 s during the failed ~30 s boot. > > == Notes == > - Not related to suspend/resume (one suspend cycle in 14 days). > - Not correlated with package/kernel changes (same kernel and firmware in > all affected boots; intermittent for months). > - Similar reports: Lenovo IdeaPad + mainline 7.0 kernel with dpcd/DMUB > errors and black screen (CachyOS forum, Apr 2026); Launchpad #2144530 > (amdgpu DC/DMUB regression, different hardware). > - Workaround `amdgpu.dcdebugmask=0x10` (disable PSR) is known for this > symptom class but NOT yet tested here. > - Full journalctl output of failed and successful boots available on > request. > > ProblemType: Bug > DistroRelease: Ubuntu 26.04 > Package: linux-image-7.0.0-38-generic 7.0.0-38.38 > ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14 > Uname: Linux 7.0.0-38-generic x86_64 > ApportVersion: 2.34.1-0ubuntu0.1 > Architecture: amd64 > CasperMD5CheckResult: unknown > CurrentDesktop: KDE > CurrentDmesg: Error: command ['pkexec', 'dmesg'] failed with exit code 127: > pkexec must be setuid root > Date: Wed Oct 7 09:54:31 2026 > InstallationDate: Installed on 2026-06-11 (118 days ago) > InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 > (20260423) > MachineType: LENOVO 83KA > ProcFB: 0 amdgpudrmfb > ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic > root=UUID=6c69ad4e-ec71-4205-9946-0bfb2532d27e ro quiet splash > PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No > PulseAudio daemon running, or not running as session daemon. > SourcePackage: linux > UpgradeStatus: No upgrade log present (probably fresh install) > acpidump: Error: command ['pkexec', > '/usr/share/apport/dump_acpi_tables.py'] failed with exit code 127: pkexec > must be setuid root > dmi.bios.date: 10/20/2025 > dmi.bios.release: 1.26 > dmi.bios.vendor: LENOVO > dmi.bios.version: QACN26WW > dmi.board.asset.tag: No Asset Tag > dmi.board.name: LNVNB161216 > dmi.board.vendor: LENOVO > dmi.board.version: SDK0T76463WIN > dmi.chassis.asset.tag: No Asset Tag > dmi.chassis.type: 10 > dmi.chassis.vendor: LENOVO > dmi.chassis.version: IdeaPad Slim 3 15AHP10 > dmi.ec.firmware.release: 1.23 > dmi.modalias: > dmi:bvnLENOVO:bvrQACN26WW:bd10/20/2025:br1.26:efr1.23:svnLENOVO:pn83KA:pvrIdeaPadSlim315AHP10:rvnLENOVO:rnLNVNB161216:rvrSDK0T76463WIN:cvnLENOVO:ct10:cvrIdeaPadSlim315AHP10:skuLENOVO_MT_83KA_BU_idea_FM_IdeaPadSlim315AHP10:pfaIdeaPadSlim315AHP10: > dmi.product.family: IdeaPad Slim 3 15AHP10 > dmi.product.name: 83KA > dmi.product.sku: LENOVO_MT_83KA_BU_idea_FM_IdeaPad Slim 3 15AHP10 > dmi.product.version: IdeaPad Slim 3 15AHP10 > dmi.sys.vendor: LENOVO > > To manage notifications about this bug go to: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169805/+subscriptions > > ** Attachment added: "bootlog-b3-failed.log" https://bugs.launchpad.net/bugs/2169805/+attachment/6008988/+files/bootlog-b3-failed.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2169805 Title: [7.0.0-38] amdgpu: DMUB/DMCUB errors + intermittent black screen on boot on Lenovo IdeaPad Slim 3 15AHP10 (HawkPoint1 1002:1900) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169805/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
