I am using my U3818DW monitor with a Latitude 7480 via a USB-C connection. I have some peripherals (Logitech keyboard/mice, audioengine D1 DAC ) that are connected to the USB hub in the monitor that I want to use no matter which device is connected via USB-C cable.
The problem I am facing now is that the peripherals connected to the U3818DW USB hub only works 50% of the time and most of the time its not detected by my Latitude 7480.I have tried to reboot my Latitude 7480 and U3818DW while connected to the USB-C cable to the U3818DW to see if it detects the devices, but it does not work most of the time.
When you're connected via USB-C, shouldn't the cable work as an upstream/downstream all the time? Also listing a screenshot of the device manager during the issue.
The U3818DW User's Guide pages 6, 29, 56, states that to use the U3818DW USB hub correctly, you must connect the provided USB 3.0 upstream cable to the computer USB 3.0 port. Just using the USB Type-C cable may provide enough power to the U3818DW USB hub, but due to the high resolution of 3840x1600 required by the U3818DW, you will be limited to USB 2.0 speed and you could experience "drops" of the U3818DW USB hub by the operating system.
Based on your troubleshooting, you have proven that the USB Type-C connection from the Latitude 7480 is intermittently failing to drive the U3818DW USB hub. This could be a Latitude 7480 driver issue or an operating system power management setting, or simply that it cannot push it. That being the case, my advice is to simply connect the provided U3818DW USB 3.0 upstream cable to the U3818DW USB upstream port and the other end to the Latitude 7480 right side USB 3.0 port with PowerShare. This will remove the U3818DW USB hub from the intermittent USB Type-C.