Public bug reported: Hi there! I have a Lenovo Carbon X1 and I use an external HP Z27 4K monitor. I have the monitor connected to the Lenovo laptop using a HDMI cable. I also have the same monitor connected to a Dell desktop computer using a DP cable.
I can change the selected input on the monitor from HDMI (laptop) to DP (desktop). The problem is that when I change it back, both the external monitor AND the laptop screen flicker as if I had physically plugged in the monitor. Checking dmesg, I'm getting the following messages: ``` [616849.330989] [drm:drm_dp_dual_mode_detect [drm_kms_helper]] *ERROR* Unexpected DP dual mode adaptor ID 50 [616853.593595] [drm:drm_dp_dual_mode_detect [drm_kms_helper]] *ERROR* Unexpected DP dual mode adaptor ID 50 ``` Sometimes I get back my desktop, but more often then not the external monitor is stuck as 1920*1080 and I have to use `autorandr` to fix that. ``` lsb_release -rd Description: Ubuntu 21.04 Release: 21.04 ``` ``` uname -a Linux my-laptop 5.11.0-22-generic #23-Ubuntu SMP Thu Jun 17 00:34:23 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux ``` ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Attachment added: "version.log" https://bugs.launchpad.net/bugs/1936868/+attachment/5511963/+files/version.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1936868 Title: monitor flickers when input is changed back To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1936868/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs