I had the same problem with an Dell U2311H monitor. HDMI only is not working but surprisingly it worked when I linked the monitor with an extra USB cable to use the USB ports of the monitor as USB hub for the keyboard and mouse
I had the same problem with an Dell U2311H monitor. HDMI only is not working but surprisingly it worked when I linked the monitor with an extra USB cable to use the USB ports of the monitor as USB hub for the keyboard and mouse