Hi,

Yes — the problem is present on 7.0.0-34, and in fact on every kernel I
have journal history for (7.0.0-22, -27, -28, -30, -31, -34, -38). On this
machine it is not a regression introduced between -34 and -38.

journalctl statistics (~277 boots total):
- 7.0.0-34: 20 boots, 3 with the DMCUB error flood + black screen
  (68/89/90 errors), requiring a power cycle
- 7.0.0-31: ~76 boots, 13 failed the same way
- 7.0.0-38: ~35 boots, 8 failed the same way
- the "dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us" line
  appears on ALL of these kernels (e.g. 93x under -31, 19x under -34),
  long before -38

Compared to bug #2169181 my case looks different:
- hardware: APU (AMD HawkPoint1 1002:1900, iGPU driving the eDP panel,
  Lenovo IdeaPad Slim 3 15AHP10), not a discrete RX 9060 desktop
- symptom: not flickering/pixel artifacts, but an intermittent black
  screen on cold boot (~15-20% of power-ons) with a flood of
  "Error queueing DMUB command: status=2" /
  "dc_dmub_srv_log_diagnostic_data: DMCUB error" (~90-220 per failed
  boot, ~1/s for ~30s) plus "kwin_wayland_drm: atomic commit failed:
  Device or resource busy"; a warm reboot virtually always succeeds
- affected boots are almost always cold boots, not load-related

In some cases the desktop environment still shows. But it leads to
flickering and stutters.


Ross Porter <[email protected]> schrieb am Donnerstag, 8. Oktober 2026 
um 06:10:

> Hi,
> 
> Thanks for submitting a bug report. The 'workqueue: 
> dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us' seems to be the 
> same as https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169181
> Does the problem still appear on kernel 7.0.0-34?
> 
> --
> 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
> 
>

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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)

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