I have a Lenovo T-580 Laptop with i5-8350U running Windows 10 build 1809 with latest drivers. The T580 has two USB-C ports. One is connected to a CSV-1550 MST hub, which is driving QHD and WUXGA 60Hz displays. The other USB-C is driving a 4k@60Hz display. Everything works fine after hitting the reset button on the MST hub, but there are a couple of problems.
1) When Windows turns off the displays after detecting inactivity, the MST won't wakeup/resume. I press a key or shake the mouse to wake up the system and the 4k display wakes up, but the displays connected to the MST hub don't turn on. I have a to hit the reset button on the MST to get them to turn on. How do I get MST to wake up/resume automatically?
2) After using the system for several hours, sometimes the MST monitors start flickering simultaneously (go blank for several seconds then come back). The 4k monitor stays on.
I used the same setup and cables from a loaner Lenovo Ultra Dock (40AJ), which uses the same USB-C ports and has a MST hub inside it and didn't experience either of these problems.
The device manager shows an Unknown USB device (Device Descriptor Request Failed). I didn't check to see if they unknown USB device was present.