USB-C video problems

[cackletinkle]

I have a universal ThinkPad USB-C Dock (40A9)

-the dock is powered by 135W lenovo ac adapter (yellow port on the left)
-a dell monitor is connected using a DP cable from the dock
-mouse and keyboard are on a KVM which interfaces to the dock via USB

the above setup works just fine using my work laptop, a lenovo T490 with a USB-C cable connecting the laptop and the dock. However, when i tried that with AMR5 5800U by connecting the USB-C cable to the front of AMR5 and the dock (between power port and VGA) it gets as far as showing the desktop and then a few seconds later the AMR5 powers off. I tried two different cables that work with the laptop with the same result.

-when i connect the DC19V brick and use USB-C as video out, same thing happens and the machine shuts down.
-USB-C as power/hub and DP as video out - crash
+when i connect the DC19V brick, unplug DisplayPort from the dock and plug it in directly to the back of AMR5, leaving USB-C plugged in (essentially as a glorified hub) everything is ok

latest windows updates and drivers applied and i'm stuck. no USB-C monitor to try that directly without a dock and no other dongles/adapters i have handy. any ideas on what else to troubleshoot? any specific BIOS settings? i've reset it to defaults already and no change
it doesn't matter which GFX option it's set to except i haven't tried 'disabled'

when on DP directly it's as pictured below

AMI Graphic Output Protocol Policy.png (9.46 KiB) Viewed 6550 times

when display is via USB-C it changes to DFP1_DP i think - not sure if that makes any difference

safe mode without networking was ok on one occasion but another time it crashed so that's inconclusive
come to think of it, it never crashes in the BIOS, so i'm leaning to drivers or some programs/services that start in windows?
it's a bare bones installation as i was just doing some stability testing and tweaking W10 (passmark, furmark, cinebench, prime95 etc. all worked flawlessly when USB-C was not used.
I might try a clean install and start everything via USB-C but that's last resort for now so if you have any ideas i'm all ears!

[barry777]

The ThinkPad USB-C Dock has not been tested so far; it may be caused by incompatibility, and it is recommended to try another docking station.

[cackletinkle]

thx! didn't really occur to me it could be the dock as it is an older one so i figured it should be compatible. I'll see if i can find a USB-C monitor in the office. i know we have universal kensington docks so maybe one of those would work.

[dragonpoo]

The ThinkPad USB-C Dock has not been tested so far; it may be caused by incompatibility, and it is recommended to try another docking station.

Barry, are there specific docking stations that your team has tested and qualified to work? If you have recommendations, that may help others.

[barry777]

At present, we have tested UGREEN and Anker's expansion docks to work normally.

[cackletinkle]

a quick update.. i tried a bunch of GaN chargers and cables and none worked properly to power the AMR5. a fairly new 45W lenovo laptop usb-c brick was not sufficient either. i got a usb digital tester and found out that regardless of what dock you use, you need to power it with at least 65W PD. I also tested 65W and 135W lenovo laptop chargers and at boot, the power requirement jumps to full 65W and on the 135W charger i saw it briefly hit 70W!

boot.png (614.68 KiB) Viewed 6086 times

i bought a generic USB-c dock and using the 65W lenovo brick i found:


in silent mode, it peaks around 32W

silent.jpg (100.01 KiB) Viewed 6086 times

in auto mode, it peaks around 40W

auto.jpg (91 KiB) Viewed 6086 times

and in performance, it hits 52W

performance.jpg (110.5 KiB) Viewed 6086 times

surprisingly, this cheap dock worked fine although the setup was clunky (usb-c to hdmi video on this dock that then used a hdmi-vga dongle..lol) i did learn that not all GaN chargers are made to full specs.. neither are some of the usb-c cables.. for now, a portable setup includes:

• lenovo 65W usbc brick / OEM brick
• Qeefun hub* / not required, unless to use as SD reader or USB expansion
• HDMI cable to TV/monitor / would use one anyway just plugged to the back of AMR5

aaaannd i just realized that it doesn't save me anything and just adds an item that's not really needed
but good to know that if the power brick dies, it can be replaced by a 65W+ usb-c one

[barry777]

Yes, current docking station power supply compatibility is not very good. You can use a 65W or 100W power adapter to provide power to the AMR5 (connect to the Type-C interface on the front of the AMR5).