01-21-2019 11:40 AM
A T470s on the UltraDock running two Samsung 3840x2160 monitors scaled to 2560x1440 at 29Hz. One monitor uses the docking station's HDMI output, the other uses the DVI output. Nine times out of ten reboots, both monitors come up fine. It's that tenth time that is challenging - Both monitors will comes up normally, but the HDMI one intermittently blinks a partial screen, rectangular image horizontally offset from the actual background image. It flashes two/three times and then disappears. Then a minute later it's back. The size of the partial image varies, the flashing interval varies, but a reboot tends to fix the problem.
I've swapped HDMI1 and HDMI2 plugs on the monitors, I've switched the actual monitors, and I've switched the cables. But after ten or so reboots, the image shows up on the HDMI monitor again. It's annoying, but sending the T470s in would take time, and the problem could be at my end - Cable length? Cable routing? I just don't know.
Any thoughts out there?
(Maybe someday I'll capture that "image" and post it, but so far it's as hard to capture as it is to understand.)