[Bug 2145078] [NEW] Regression: Kubuntu 26.04 with kernel 7.0.0-7-generic hangs at resume from suspend with flickering screen

Public bug reported:

Since the kernel upgrade to 7.0.0-7-generic, my test installation of Kubuntu 26.04 hangs with a flickering screen when I resume my PC from suspend-to-RAM.
This is a regression from linux 6.19.0-9-generic.

STEPS TO REPRODUCE
1. Boot Kubuntu 26.04 with kernel 7.0.0-7-generic, login to KDE Plasma Desktop.
2. Suspend-to-RAM.
3. Power on again.

ACTUAL RESULT
PC hangs with flickering screen (sample video attached below). Key presses, like for opening a TTY or Ctrl+Alt+Delete, do nothing. Only exception: SysRq+B for rebooting the machine still works.

EXPECTED RESULT
Suspend works :)

ADDITIONAL INFORMATION
If I boot the older kernel 6.19.0-9-generic, suspend works just fine, so it seems like a regression in 7.0.0-7-generic.
I have disabled the KDE screen locker.

ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-7-generic 7.0.0-7.7
ProcVersionSignature: Ubuntu 7.0.0-7.7-generic 7.0.0-rc3
Uname: Linux 7.0.0-7-generic x86_64
ApportVersion: 2.33.1-0ubuntu4
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Sat Mar 21 12:41:35 2026
InstallationDate: Installed on 2026-03-05 (16 days ago)
InstallationMedia: Kubuntu 26.04 LTS "Resolute Raccoon" - Daily amd64 (20260301)
MachineType: ASUS System Product Name
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-7.0.0-7-generic root=UUID=542ff2d9-34c9-43b5-a08f-b3751680c912 ro rootflags=subvol=@ quiet splash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RfKill:

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/04/2026
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3636
dmi.board.asset.tag: Default string
dmi.board.name: PRIME A520M-E
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr3636:bd01/04/2026:br5.17:svnASUS:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnPRIMEA520M-E:rvrRevX.0x:cvnDefaultstring:ct3:cvrDefaultstring:skuSKU:pfaTobefilledbyO.E.M.:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.sku: SKU
dmi.product.version: System Version
dmi.sys.vendor: ASUS

** Affects: linux (Ubuntu)
Importance: Undecided
Status: New


** Tags: amd64 apport-bug resolute wayland-session

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https://bugs.launchpad.net/bugs/2145078

Title:
Regression: Kubuntu 26.04 with kernel 7.0.0-7-generic hangs at resume
from suspend with flickering screen

Status in linux package in Ubuntu:
New

Bug description:
Since the kernel upgrade to 7.0.0-7-generic, my test installation of Kubuntu 26.04 hangs with a flickering screen when I resume my PC from suspend-to-RAM.
This is a regression from linux 6.19.0-9-generic.

STEPS TO REPRODUCE
1. Boot Kubuntu 26.04 with kernel 7.0.0-7-generic, login to KDE Plasma Desktop.
2. Suspend-to-RAM.
3. Power on again.

ACTUAL RESULT
PC hangs with flickering screen (sample video attached below). Key presses, like for opening a TTY or Ctrl+Alt+Delete, do nothing. Only exception: SysRq+B for rebooting the machine still works.

EXPECTED RESULT
Suspend works :)

ADDITIONAL INFORMATION
If I boot the older kernel 6.19.0-9-generic, suspend works just fine, so it seems like a regression in 7.0.0-7-generic.
I have disabled the KDE screen locker.

ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-7-generic 7.0.0-7.7
ProcVersionSignature: Ubuntu 7.0.0-7.7-generic 7.0.0-rc3
Uname: Linux 7.0.0-7-generic x86_64
ApportVersion: 2.33.1-0ubuntu4
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Sat Mar 21 12:41:35 2026
InstallationDate: Installed on 2026-03-05 (16 days ago)
InstallationMedia: Kubuntu 26.04 LTS "Resolute Raccoon" - Daily amd64 (20260301)
MachineType: ASUS System Product Name
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-7.0.0-7-generic root=UUID=542ff2d9-34c9-43b5-a08f-b3751680c912 ro rootflags=subvol=@ quiet splash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RfKill:

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/04/2026
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3636
dmi.board.asset.tag: Default string
dmi.board.name: PRIME A520M-E
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr3636:bd01/04/2026:br5.17:svnASUS:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnPRIMEA520M-E:rvrRevX.0x:cvnDefaultstring:ct3:cvrDefaultstring:skuSKU:pfaTobefilledbyO.E.M.:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.sku: SKU
dmi.product.version: System Version
dmi.sys.vendor: ASUS

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