Lenovo Doc doesn't support more than 1 external display at a time

Framework Laptop
#1

I have a Lenovo ThinkPad USB-C Dock Gen 2 docking station with a DIY framework laptop. The two displays connected are a 4K (3840x2160) monitor via a DisplayPort cable and a 1920x1200 via DVI-to-DP adapter. I’ve had this setup run well before, but on a different Lenovo docking station with a different laptop (ThinkPad T14 Gen1 AMD).

I see that this particular docking station has been “vetted” in the dock megathread (USB-C/Thunderbolt Dock Megathread), but only for Windows 10. I’m currently running Manjaro i3 (but using Qtile as the actual window manager).

I can get either the 4K + eDP, or 1920x1200 + eDP working, but not all three or just the 4K + 1920x1200 monitor. The error message I get from arandr (and xrandr) is:

xrandr: Configure crtc N failed

where N is some number between 0 and 2. There are bunch of attempted fixes for this error message online, but I haven’t be successful with any of them. This includes:

  • Attempting with different refresh rates
  • Turning on/off one monitor at a time
  • Attempting with different resolutions

Anyone else run into this?

#2

Update: just in case, I attempted to change kernels to see if that would have any effect. 5.14, 5.10, and 5.12 all had the same error and general behavior.

#3

I did have something similar, but with a completely different dock.

My much cheaper dock has 2 HDMI ports and a VGA port. I found that I could use EITHER the HDMI port OR the VGA port but not both at the same time.

I just changed monitors (now 2 X 2K) so I can now use both HDMI ports and they both work - sort of. With one port connected I could connect my new monitor 2560x1440@75Hz or my old monitor 2560x1440@60Hz, the maximum each can support. But with both connected they are in an odd 2048x1152@60Hz resolution and refresh rate. Sometimes one wants to run at 1920x1080@60Hz. Sometimes one isn’t detected at all. It usually works but the results are random.

I would say Linux just doesn’t support the video converters in these hubs perfectly.

I’m using Linux Mint 20.2 with kernel 5.14, which is very bleeding edge for Mint and not really officially supported.

This video is all presented to the hub in DP Alt Mode, so the video inside the hubs are converted from DP, usually into HDMI. But most of the hubs I saw also had an extra alternative video output - there were a lot of VGA (because it’s cheap!) but I did see one DP and even one DVI. These extra ports seem to be a little more problematic. In your case, it’s going through 2 converters, first from DP (Alt) then to DVI then your converter back to DP. Something gets lost in this double conversion perhaps. DP Alt to HDMI seems to work OK.

I can’t offer any help because I’m just guessing and haven’t done much troubleshooting, but I did want to say I’m experiencing something similar and I will be following this thread.

#4

Weird. Yeah, I figured it might be something to do with the DP-to-DVI convertor, but I haven’t had an issue with it up till now. The 1920x1200 monitor does have a DP port on it, I just don’t have a DP cable at the moment to test the theory though.

I’ve also ordered a Cable-Matters docking station (I need two anyways), so I’ll see how that one works when I get it in.

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#5

Update: Got in the Cable-Matters Docking station (M#: ‎107034-SIL). With the DP-to-DVI adapter, the docking station doesn’t even recognize the existence of the 1920x1200 monitor.

I’ll try to get my hands on a DP-to-DP cable to verify that it’s just the converter.

#6

Update 2: Got a DP-to-DP cable for the 1920x1200 monitor and it works perfectly with the CableMatters docking station; I’m able to run all three monitors (4k, 1920, and the laptop display) at the same time without issues.

Note that I haven’t tested this with the Lenovo dock and probably don’t plan to (I’d have to untether it from my desk at home and bring it to work), but I’m fairly certain that I’d probably work with that. Looks like the issue was with Framework’s DP-Alt functionality not liking the DVI-to-DP adapter rather than an issue with the docking station itself.

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