** Description changed: - On a Lenovo laptop with AMD Rembrandt / Radeon 680M, external monitors connected through a Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock often stay dark when the system is booted while already docked. Kernel logs show repeated USB enumeration failures on the dock path, Thunderbolt dock connect/disconnect, amdgpu DP AUX/DPCD/MST link failures, and a warning in dcn31_program_compbuf_size. A manual MST reprobe via /sys/kernel/debug/dri/0000:33:00.0/amdgpu_dm_trigger_hpd_mst caused a reproducible amdgpu kernel oops in trigger_hpd_mst_set. - ``` - - ## Reproduction steps to paste - - ```text - 1. Connect the laptop to a Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock with two external DP monitors attached. - 2. Boot the machine while already docked. - 3. Observe that the external monitors sometimes remain dark. - 4. Check kernel logs for repeated usb 8-1 enumeration failures, Thunderbolt disconnects, and amdgpu MST / AUX / DPCD errors. - - Additional diagnostic reproduction: - 5. When the docked displays are in a working MST state, write "1" to /sys/kernel/debug/dri/0000:33:00.0/amdgpu_dm_trigger_hpd_mst. - 6. Observe a kernel oops in trigger_hpd_mst_set [amdgpu]. - ``` - - ## Expected result - - ```text - The dock should enumerate cleanly during boot, both external monitors should come up reliably, and an MST hotplug reprobe should not crash the kernel. - ``` - - ## Actual result - - ```text - During docked boot, the dock path repeatedly fails USB enumeration, Thunderbolt disconnects after appearing, amdgpu DP MST link setup fails, and the external monitors may remain dark. A manual MST reprobe can trigger a kernel oops in amdgpu. - ``` - - ## High-signal details to include - - - Kernel: `7.0.0-27-generic` - - GPU: `AMD Rembrandt / Radeon 680M` - - BIOS: `R22ET81W (1.51)`, `2026-04-10` - - Dock: `Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock` - - No dock firmware update was offered by `fwupdmgr` - - No system firmware or EC update was pending - - ## Key log lines to mention - - These are the most important patterns: - amdgpu ... [drm] DPIA AUX failed on 0x2c0(1), error 7 - thunderbolt 0-2: device disconnected - amdgpu ... [drm] *ERROR* dpcd_set_link_settings ... - amdgpu ... [drm] *ERROR* Sending link address failed with -5 - WARNING: ... dcn31_program_compbuf_size - [drm:trigger_hpd_mst_set [amdgpu]] *ERROR* DM_MST: Failed to detect dc link! - BUG: unable to handle page fault ... - RIP: trigger_hpd_mst_set+0x13b/0x1b0 [amdgpu] - ``` - - ## Files prepared locally - - - Main report: [UBUNTU_BUGREPORT_DP_DOCK_MST.md](/home/tstocke/gitlab.ethz.ch/eth-config-tool/UBUNTU_BUGREPORT_DP_DOCK_MST.md) - - Filing guide: [UBUNTU_BUGREPORT_DP_DOCK_MST_FILING.md](/home/tstocke/gitlab.ethz.ch/eth-config-tool/UBUNTU_BUGREPORT_DP_DOCK_MST_FILING.md) - - ## Suggested filing workflow - - Run: - - ```bash - ubuntu-bug linux - ``` - - Then in the bug text: - - 1. Use the bug title from this file. - 2. Paste the short summary. - 3. Paste the reproduction steps. - 4. Paste expected and actual result. - 5. Attach or paste the contents of `UBUNTU_BUGREPORT_DP_DOCK_MST.md`. - - ## Optional extra attachments - - If Apport does not automatically gather enough information, attach the output of: - - ```bash - uname -a - journalctl -b -k - sudo lspci -nnk - sudo fwupdmgr get-devices - sudo fwupdmgr get-updates - sudo boltctl list - sudo cat /sys/kernel/debug/dri/0000:33:00.0/amdgpu_mst_topology - ``` - - ## Note - - The `trigger_hpd_mst_set` reprobe was used only as a diagnostic step. It should not be treated as a safe workaround, because it caused a kernel oops on this system. - ```text - usb 8-1: Device not responding to setup address - usb 8-1: device not accepting address ..., error -71 - thunderbolt 0-2: Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock + On a Lenovo laptop with AMD Rembrandt / Radeon 680M, external monitors + connected through a Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock + often stay dark when the system is booted while already docked. Kernel + logs show repeated USB enumeration failures on the dock path, + Thunderbolt dock connect/disconnect, amdgpu DP AUX/DPCD/MST link + failures, and a warning in dcn31_program_compbuf_size. A manual MST + reprobe via /sys/kernel/debug/dri/0000:33:00.0/amdgpu_dm_trigger_hpd_mst + caused a reproducible amdgpu kernel oops in trigger_hpd_mst_set. + + ## Reproduction steps + + 1. Connect the laptop to a Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock with two external DP monitors attached. + 2. Boot the machine while already docked. + 3. Observe that the external monitors sometimes remain dark. + 4. Check kernel logs for repeated usb 8-1 enumeration failures, Thunderbolt disconnects, and amdgpu MST / AUX / DPCD errors. + + Additional diagnostic reproduction: + 5. When the docked displays are in a working MST state, write "1" to /sys/kernel/debug/dri/0000:33:00.0/amdgpu_dm_trigger_hpd_mst. + 6. Observe a kernel oops in trigger_hpd_mst_set [amdgpu]. + + ## Expected result + + The dock should enumerate cleanly during boot, both external monitors + should come up reliably, and an MST hotplug reprobe should not crash the + kernel. + + + ## Actual result + + During docked boot, the dock path repeatedly fails USB enumeration, + Thunderbolt disconnects after appearing, amdgpu DP MST link setup fails, + and the external monitors may remain dark. A manual MST reprobe can + trigger a kernel oops in amdgpu. + + + ## High-signal details to include + + - Kernel: `7.0.0-27-generic` + - GPU: `AMD Rembrandt / Radeon 680M` + - BIOS: `R22ET81W (1.51)`, `2026-04-10` + - Dock: `Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock` + - No dock firmware update was offered by `fwupdmgr` + - No system firmware or EC update was pending + + ## Key log lines to mention + + These are the most important patterns: + amdgpu ... [drm] DPIA AUX failed on 0x2c0(1), error 7 + thunderbolt 0-2: device disconnected + amdgpu ... [drm] *ERROR* dpcd_set_link_settings ... + amdgpu ... [drm] *ERROR* Sending link address failed with -5 + WARNING: ... dcn31_program_compbuf_size + [drm:trigger_hpd_mst_set [amdgpu]] *ERROR* DM_MST: Failed to detect dc link! + BUG: unable to handle page fault ... + RIP: trigger_hpd_mst_set+0x13b/0x1b0 [amdgpu] + + + ## Note + + The `trigger_hpd_mst_set` reprobe was used only as a diagnostic step. It + should not be treated as a safe workaround, because it caused a kernel + oops on this system. + + usb 8-1: Device not responding to setup address + usb 8-1: device not accepting address ..., error -71 + thunderbolt 0-2: Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-27-generic 7.0.0-27.27 ProcVersionSignature: Ubuntu 7.0.0-27.27-generic 7.0.6 Uname: Linux 7.0.0-27-generic x86_64 ApportVersion: 2.34.0-0ubuntu2 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Tue Jul 14 14:58:10 2026 InstallationDate: Installed on 2025-03-12 (489 days ago) InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215) MachineType: LENOVO 21CRS08P00 ProcEnviron: - LANG=en_US.UTF-8 - PATH=(custom, no user) - SHELL=/bin/bash - TERM=xterm - XDG_RUNTIME_DIR=<set> + LANG=en_US.UTF-8 + PATH=(custom, no user) + SHELL=/bin/bash + TERM=xterm + XDG_RUNTIME_DIR=<set> ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-27-generic root=/dev/mapper/ubuntu--vg-ubuntu--lv ro quiet splash crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M SourcePackage: linux UpgradeStatus: Upgraded to resolute on 2026-05-08 (67 days ago) dmi.bios.date: 04/10/2026 dmi.bios.release: 1.51 dmi.bios.vendor: LENOVO dmi.bios.version: R22ET81W (1.51 ) dmi.board.asset.tag: Not Available dmi.board.name: 21CRS08P00 dmi.board.vendor: LENOVO dmi.board.version: SDK0K17763 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.ec.firmware.release: 1.33 dmi.modalias: dmi:bvnLENOVO:bvrR22ET81W(1.51):bd04/10/2026:br1.51:efr1.33:svnLENOVO:pn21CRS08P00:pvrThinkPadT14sGen3:rvnLENOVO:rn21CRS08P00:rvrSDK0K17763WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21CR_BU_Think_FM_ThinkPadT14sGen3:pfaThinkPadT14sGen3: dmi.product.family: ThinkPad T14s Gen 3 dmi.product.name: 21CRS08P00 dmi.product.sku: LENOVO_MT_21CR_BU_Think_FM_ThinkPad T14s Gen 3 dmi.product.version: ThinkPad T14s Gen 3 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/2160619 Title: amdgpu: DP MST via Lenovo ThinkPad Universal Thunderbolt 4 Smart Dock fails at boot and trigger_hpd_mst_set causes kernel oops To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2160619/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
