I tried the maniline kernel with bisect method. We need bisect the patch from v5.10.57 to v5.11-rc2, and v5.11-rc1 didn't provide deb package because of building failure.
v5.10 works fine v5.10.57 works fine v5.11 doesn't work v5.11-rc4 doesn't work v5.11-rc2 doesn't work -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1938999 Title: External displays not working on Thinkpad T490 with ThinkPad Thunderbolt 3 Dock Status in linux package in Ubuntu: Confirmed Bug description: I have two external displays chained via Display port connected to the ThinkPad Thunderbolt 3 Dock. They are working with kernel 5.8.0-63 but not with the new 5.11.0-25 kernel. I could reproduce this behavior several times for both kernels, as follows: I booted up with disconnected dock, logged in, then I connected it, disconnected it, and connected it again. With the 5.11.0-25 kernel the external displays go black; the main screen turns off and on several times. Sometimes the main screen remains working, but UI is lagging. I'm attaching the logs. Two separate boots for each variant are marked 'a'/'b'. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1938999/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
