Root Cause & Verified Workaround The link fails during Time Management Unit (TMU) synchronization when low-power link states (CL1/CL2) are active.
Workaround: Booting with the kernel parameter thunderbolt.clx=0 (and usbcore.autosuspend=-1) completely resolves the disconnect loop and stabilizes the 40 Gb/s link and DisplayPort MST tunnels. Proposed Fix Please consider adding a hardware quirk in drivers/thunderbolt/quirks.c for Intel Goshen Ridge docks (0x0108:0x2031) attached to AMD Rembrandt / Yellow Carp USB4 host routers (1022:162e / 1022:162f) to automatically disable CLx by default. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2165852 Title: [AMD Rembrandt + ThinkPad TB4 Dock 40B0] Infinite disconnect loop: "failed to enable TMU" / "USB3 tunnel creation failed" without thunderbolt.clx=0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-7.0/+bug/2165852/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
