I'm hitting the same issue. Here's a log from the command: ~[08:50]> journalctl --boot=-1 > 2021-08-10_i915_drm_link_training_unsuccessful_error.log
Booting back into the 5.8 kernel allows my dock display to work again. It looks like this might be the same issue: https://bugs.archlinux.org/task/70135 ** Attachment added: "2021-08-10_i915_drm_link_training_unsuccessful_error.log" https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.11/+bug/1939297/+attachment/5516982/+files/2021-08-10_i915_drm_link_training_unsuccessful_error.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1939297 Title: External monitors are black (connected through USB-C hub) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.11/+bug/1939297/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
