Blank screen after reconnecting DP monitors using KVM with clamshell closed
Hi,
I run Ubuntu 18.04 on a Dell Precision 7540. Most of the time I use this through a Dell WD19DC dock. The dock is connected to a Trendnet TK-240DP KVM Switch via two displayport connections.
If I have the laptop clamshell closed, like I normally do, and switch my KVM to the other computer, and then switch back, my monitors enter and stay in power saving mode. This happens 100% of the time. Most of the time (95%?), I am able to recover the screens by pressing Control-Alt-F3, waiting a few seconds, and then pressing Control-Alt-F2. The problem does not usually happen (5%?) if the clamshell is left open.
I have tested Linux kernel versions 4.15.0-1079-oem, 5.0.0-1047-oem-osp1, 5.5.0-050500rc6-generic and 5.7.0-994-generic (from https://kernel.ubuntu.com/~kernel-ppa/mainline/drm-tip/current/). These are all built by Ubuntu. I have not noticed any difference in behavior between these kernel versions.
I am attaching a dmesg log with drm.debug=0x1e
.drm.log.bz2
Any assistance would be greatly appreciated. This problem has been driving me crazy, and basically makes the KVM unusable.
Thanks,
Ed