Latitude 5420 and DisplayLink issues
 

Just got a new Latitude 5420, previous laptop was a Latitude 5400. Have 3 monitors

Since I can only run one 1440p monitor off the dock, the other monitor is connected via HDMI thru the laptop, and another one through a DL-165 DVI/VGA adapter connect via USB 2.0 in the dock.

Ever since getting this laptop, I noticed the lights on my keyboard would flash and then the last keystroke entered would begin to repeat on the screen until connection was restored. No USB disconnect/reconnect sound. Mouse would freeze for a few seconds too.

Took me awhile to troubleshoot, but it turns out the DL-165 adapter was the root cause. Connected either thru a monitor hub going into the docking station or plugged directly into the docking station would cause USB device issues. Same with connecting to the USB ports on the laptop.

The DisplayLink drivers are fully up to date, i tried another DisplayLink adapter and same issues. Also tried my coworkers WD19 Non TB dock aswell and same issues.

None of this happened on my latitude 5400, not really sure what the issue is and was hoping to get some answers here.

I work in IT and a few people in the company have a setup similar to mine, this might be a future headache if I cant figure it out, unfortunately we do not supply Thunderbolt docks so this is the best we can do here.

Laptop is fully updated via Dell Command Updates

Dock's firmware is fully up to date.

The only displaylink adapters i have are a Tripp lite DL-165 and a IO Gear DisplayLink Certfied VGA one, both produced the same issues.


Thanks for the help.

When you say, 'the dock', to what specific brand and model of device are you referring?


My impression based on your description is that in some instances pressing a single key on the keyboard results in the single key press being recognized multiple times. For example, like thissssssss

Is my impression correct?

Is the 5400 system still available to test with?

The docks I've tried were a Dell WD 15 non thunderbolt and a Dell WD19 non thunderbolt

Yep, that's exactly what happens, my external keyboard has LED lights and they will blink and then lock in the last keyword pressed until connection is restored. My mouse will also lock up and freeze for a similar amount of time, about 1 to 2 seconds. The second I disconnected the DisplayLink adapter, all the issues went away

It also didn't matter if i plugged it into the dock, a usb hub connected into the dock, or directly into the laptop itself

happens with both USB 2.0 and 3.0 ports


Yes it is, i have it on the side available, Perks of working in IT, we have all the hardware :)

Given that you still have the previous hardware available, it would be ideal to test the behavior again with the original laptop, making sure no other variables change. Doing so would allow us to isolate if the problem is specific to the laptop, and not the external hardware.

The behavior you describe sounds similar to what others have been reported in the past, and in some of those previous cases the solution was to install a 'Dell USB-C Patch' update, which disables a power management setting for the Intel Management Engine within the Windows Registry within the host PC. The Dell update is available to download from here --> https://downloads.dell.com/FOLDER034..._SETUP_ZPE.exe

If you are wary of applying this update, the contents can be extracted with a utility such as 7zip so you can see precisely what the update does (the executable is a wrapper around a simple Windows batch file).

omg....This is unbelievable.... It worked!!!! i installed the BAT file, it changed the registry, rebooted and no more problems. THANK YOU!!!

You just solved me hours of headaches with users in the company, this will help out alot for when users get their refreshed equipment which is a latitude 5420

You are most welcome :-)

I am glad to hear my suggestion helped.