Public bug reported: After upgrading from linux 7.0.0-34.34 to 7.0.0-38.38 (Ubuntu 26.04.1), external monitors on a ThinkPad P14s Gen 5 AMD show brief, single-frame horizontal bands of multicoloured garbage. It reproduces within a minute by dragging a window while the CPU is heavily loaded (e.g. a parallel dotnet build, load ~16-20). Booting 7.0.0-34-generic with an otherwise identical setup, the same test does not reproduce it.
Steps to reproduce 1. Boot 7.0.0-38-generic, two external monitors via a Lenovo ThinkPad Thunderbolt 3 Dock. 2. Start a CPU-heavy build (all cores busy). 3. Drag a window around an external monitor. Result: occasional full-width coloured noise band for one frame. Same steps on 7.0.0-34-generic: no corruption. Hardware / software - Lenovo ThinkPad P14s Gen 5 AMD (21ME001LUS), BIOS R2LET42W (1.23) - AMD Ryzen 7 PRO 8840HS, Radeon 780M [1002:1900] (HawkPoint1, rev d2), DCN 3.1.4 - Displays: internal eDP 1920x1200@60; via ThinkPad Thunderbolt 3 Dock (MST): 2x [email protected] (home) and 2x HP 27es 1920x1080@60 (office). Seen on both docks/monitor sets. - KDE Plasma 6.6.6 Wayland (kwin-wayland 4:6.6.6-0ubuntu0.1), Mesa 26.0.8-1ubuntu0.3, libdrm 2.4.131-1, linux-firmware-amd-graphics 20260319.git217ca6e4-0ubuntu3.1 - Good: 7.0.0-34.34 (upstream 7.0.14). Bad: 7.0.0-38.38. Already ruled out - Refresh rate / link bandwidth: externals moved from 69.96 Hz to native 59.95 Hz; still occurs. - GPU memory clock switching: power_dpm_force_performance_level=high (mclk 2800 / fclk 1960); still occurs on -38. - Single faulty dock or monitor: two dock units, two monitor sets. Possibly relevant (pre-existing on both kernels, every boot) thunderbolt 0000:c6:00.6: 0: failed to allocate DP resource for port 7 amdgpu 0000:c4:00.0: [drm] REG_WAIT timeout 1us * 100 tries - dcn31_program_compbuf_size line:142 WARNING: drivers/gpu/drm/amd/amdgpu/../display/dc/hubbub/dcn31/dcn31_hubbub.c:151 at dcn31_program_compbuf_size Candidate commits in the -38 changelog (stable patchset 2026-08-26, LP: #2165189), not bisected: - drm/amd/display: consolidate DCN vblank/flip handling onto ... - drm/amd/display: Handle struct drm_plane_state.ignore_damage_clips - drm/amdgpu: Fix amdgpu_bo_move() when old_mem and new_mem are both GTT Happy to test proposed kernels. 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 Date: Wed Oct 14 18:31:44 2026 InstallationDate: Installed on 2026-05-16 (151 days ago) InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423) MachineType: LENOVO 21ME001LUS ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic root=UUID=3c52581f-82b0-46a6-ac94-7015c003d432 ro quiet cryptdevice=UUID=94ecd022-6297-4de8-8989-333ff5bdc9fe:luks-94ecd022-6297-4de8-8989-333ff5bdc9fe root=/dev/mapper/luks-94ecd022-6297-4de8-8989-333ff5bdc9fe 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) WifiSyslog: dmi.bios.date: 07/28/2026 dmi.bios.release: 1.23 dmi.bios.vendor: LENOVO dmi.bios.version: R2LET42W (1.23 ) dmi.board.asset.tag: Not Available dmi.board.name: 21ME001LUS dmi.board.vendor: LENOVO dmi.board.version: SDK0T76530 WIN dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.ec.firmware.release: 1.16 dmi.modalias: dmi:bvnLENOVO:bvrR2LET42W(1.23):bd07/28/2026:br1.23:efr1.16:svnLENOVO:pn21ME001LUS:pvrThinkPadP14sGen5AMD:rvnLENOVO:rn21ME001LUS:rvrSDK0T76530WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21ME_BU_Think_FM_ThinkPadP14sGen5AMD:pfaThinkPadP14sGen5AMD: dmi.product.family: ThinkPad P14s Gen 5 AMD dmi.product.name: 21ME001LUS dmi.product.sku: LENOVO_MT_21ME_BU_Think_FM_ThinkPad P14s Gen 5 AMD dmi.product.version: ThinkPad P14s Gen 5 AMD dmi.sys.vendor: LENOVO --- ProblemType: Bug ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: KDE DistroRelease: Ubuntu 26.04 InstallationDate: Installed on 2026-05-16 (151 days ago) InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423) MachineType: LENOVO 21ME001LUS Package: linux (not installed) ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic root=UUID=3c52581f-82b0-46a6-ac94-7015c003d432 ro quiet cryptdevice=UUID=94ecd022-6297-4de8-8989-333ff5bdc9fe:luks-94ecd022-6297-4de8-8989-333ff5bdc9fe root=/dev/mapper/luks-94ecd022-6297-4de8-8989-333ff5bdc9fe splash ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. Tags: resolute wayland-session Uname: Linux 7.0.0-38-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: docker WifiSyslog: _MarkForUpload: True dmi.bios.date: 07/28/2026 dmi.bios.release: 1.23 dmi.bios.vendor: LENOVO dmi.bios.version: R2LET42W (1.23 ) dmi.board.asset.tag: Not Available dmi.board.name: 21ME001LUS dmi.board.vendor: LENOVO dmi.board.version: SDK0T76530 WIN dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.ec.firmware.release: 1.16 dmi.modalias: dmi:bvnLENOVO:bvrR2LET42W(1.23):bd07/28/2026:br1.23:efr1.16:svnLENOVO:pn21ME001LUS:pvrThinkPadP14sGen5AMD:rvnLENOVO:rn21ME001LUS:rvrSDK0T76530WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21ME_BU_Think_FM_ThinkPadP14sGen5AMD:pfaThinkPadP14sGen5AMD: dmi.product.family: ThinkPad P14s Gen 5 AMD dmi.product.name: 21ME001LUS dmi.product.sku: LENOVO_MT_21ME_BU_Think_FM_ThinkPad P14s Gen 5 AMD dmi.product.version: ThinkPad P14s Gen 5 AMD dmi.sys.vendor: LENOVO ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug apport-collected resolute wayland-session ** Tags added: apport-collected ** Description changed: After upgrading from linux 7.0.0-34.34 to 7.0.0-38.38 (Ubuntu 26.04.1), external monitors on a ThinkPad P14s Gen 5 AMD show brief, single-frame horizontal bands of multicoloured garbage. It reproduces within a minute by dragging a window while the CPU is heavily loaded (e.g. a parallel dotnet build, load ~16-20). Booting 7.0.0-34-generic with an otherwise identical setup, the same test does not reproduce it. Steps to reproduce 1. Boot 7.0.0-38-generic, two external monitors via a Lenovo ThinkPad Thunderbolt 3 Dock. 2. Start a CPU-heavy build (all cores busy). 3. Drag a window around an external monitor. Result: occasional full-width coloured noise band for one frame. Same steps on 7.0.0-34-generic: no corruption. Hardware / software - Lenovo ThinkPad P14s Gen 5 AMD (21ME001LUS), BIOS R2LET42W (1.23) - AMD Ryzen 7 PRO 8840HS, Radeon 780M [1002:1900] (HawkPoint1, rev d2), DCN 3.1.4 - Displays: internal eDP 1920x1200@60; via ThinkPad Thunderbolt 3 Dock (MST): 2x [email protected] (home) and 2x HP 27es 1920x1080@60 (office). Seen on both docks/monitor sets. - KDE Plasma 6.6.6 Wayland (kwin-wayland 4:6.6.6-0ubuntu0.1), Mesa 26.0.8-1ubuntu0.3, libdrm 2.4.131-1, linux-firmware-amd-graphics 20260319.git217ca6e4-0ubuntu3.1 - Good: 7.0.0-34.34 (upstream 7.0.14). Bad: 7.0.0-38.38. Already ruled out - Refresh rate / link bandwidth: externals moved from 69.96 Hz to native 59.95 Hz; still occurs. - GPU memory clock switching: power_dpm_force_performance_level=high (mclk 2800 / fclk 1960); still occurs on -38. - Single faulty dock or monitor: two dock units, two monitor sets. Possibly relevant (pre-existing on both kernels, every boot) thunderbolt 0000:c6:00.6: 0: failed to allocate DP resource for port 7 amdgpu 0000:c4:00.0: [drm] REG_WAIT timeout 1us * 100 tries - dcn31_program_compbuf_size line:142 WARNING: drivers/gpu/drm/amd/amdgpu/../display/dc/hubbub/dcn31/dcn31_hubbub.c:151 at dcn31_program_compbuf_size Candidate commits in the -38 changelog (stable patchset 2026-08-26, LP: #2165189), not bisected: - drm/amd/display: consolidate DCN vblank/flip handling onto ... - drm/amd/display: Handle struct drm_plane_state.ignore_damage_clips - drm/amdgpu: Fix amdgpu_bo_move() when old_mem and new_mem are both GTT Happy to test proposed kernels. 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 Date: Wed Oct 14 18:31:44 2026 InstallationDate: Installed on 2026-05-16 (151 days ago) InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423) MachineType: LENOVO 21ME001LUS ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic root=UUID=3c52581f-82b0-46a6-ac94-7015c003d432 ro quiet cryptdevice=UUID=94ecd022-6297-4de8-8989-333ff5bdc9fe:luks-94ecd022-6297-4de8-8989-333ff5bdc9fe root=/dev/mapper/luks-94ecd022-6297-4de8-8989-333ff5bdc9fe 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) WifiSyslog: dmi.bios.date: 07/28/2026 dmi.bios.release: 1.23 dmi.bios.vendor: LENOVO dmi.bios.version: R2LET42W (1.23 ) dmi.board.asset.tag: Not Available dmi.board.name: 21ME001LUS dmi.board.vendor: LENOVO dmi.board.version: SDK0T76530 WIN dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.ec.firmware.release: 1.16 dmi.modalias: dmi:bvnLENOVO:bvrR2LET42W(1.23):bd07/28/2026:br1.23:efr1.16:svnLENOVO:pn21ME001LUS:pvrThinkPadP14sGen5AMD:rvnLENOVO:rn21ME001LUS:rvrSDK0T76530WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21ME_BU_Think_FM_ThinkPadP14sGen5AMD:pfaThinkPadP14sGen5AMD: dmi.product.family: ThinkPad P14s Gen 5 AMD dmi.product.name: 21ME001LUS dmi.product.sku: LENOVO_MT_21ME_BU_Think_FM_ThinkPad P14s Gen 5 AMD dmi.product.version: ThinkPad P14s Gen 5 AMD dmi.sys.vendor: LENOVO + --- + ProblemType: Bug + ApportVersion: 2.34.1-0ubuntu0.1 + Architecture: amd64 + CasperMD5CheckResult: unknown + CurrentDesktop: KDE + DistroRelease: Ubuntu 26.04 + InstallationDate: Installed on 2026-05-16 (151 days ago) + InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423) + MachineType: LENOVO 21ME001LUS + Package: linux (not installed) + ProcFB: 0 amdgpudrmfb + ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic root=UUID=3c52581f-82b0-46a6-ac94-7015c003d432 ro quiet cryptdevice=UUID=94ecd022-6297-4de8-8989-333ff5bdc9fe:luks-94ecd022-6297-4de8-8989-333ff5bdc9fe root=/dev/mapper/luks-94ecd022-6297-4de8-8989-333ff5bdc9fe splash + ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14 + PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. + Tags: resolute wayland-session + Uname: Linux 7.0.0-38-generic x86_64 + UpgradeStatus: No upgrade log present (probably fresh install) + UserGroups: docker + WifiSyslog: + + _MarkForUpload: True + dmi.bios.date: 07/28/2026 + dmi.bios.release: 1.23 + dmi.bios.vendor: LENOVO + dmi.bios.version: R2LET42W (1.23 ) + dmi.board.asset.tag: Not Available + dmi.board.name: 21ME001LUS + dmi.board.vendor: LENOVO + dmi.board.version: SDK0T76530 WIN + dmi.chassis.asset.tag: No Asset Tag + dmi.chassis.type: 10 + dmi.chassis.vendor: LENOVO + dmi.chassis.version: None + dmi.ec.firmware.release: 1.16 + dmi.modalias: dmi:bvnLENOVO:bvrR2LET42W(1.23):bd07/28/2026:br1.23:efr1.16:svnLENOVO:pn21ME001LUS:pvrThinkPadP14sGen5AMD:rvnLENOVO:rn21ME001LUS:rvrSDK0T76530WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21ME_BU_Think_FM_ThinkPadP14sGen5AMD:pfaThinkPadP14sGen5AMD: + dmi.product.family: ThinkPad P14s Gen 5 AMD + dmi.product.name: 21ME001LUS + dmi.product.sku: LENOVO_MT_21ME_BU_Think_FM_ThinkPad P14s Gen 5 AMD + dmi.product.version: ThinkPad P14s Gen 5 AMD + dmi.sys.vendor: LENOVO -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2170909 Title: [regression] amdgpu: transient multicolour band corruption on external monitors (Hawk Point / 780M) in 7.0.0-38, not in 7.0.0-34 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2170909/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
