He’s talking about the Thinkpad USB-C Gen 2 AS40 dock
The Lenovo USB-C Gen2
Right. From the looks, it almost looks like my Dell Dock WD19TB.
Bet it’s all made in China/Taiwan - and they added some stickers for branding :}
Big OEMs share suppliers, so it could be the case
Could any FW AMD owner please upload a screenshot of the Windows 11 USB4 Panel?
I have been asked to prove that AMD is limited to a single DP connection per USB4 port, but cannot find any existing screenshot actually proving this.
For reference, this is the panel I am talking about on an Intel/TB4 machine, where it shows that as required by TB4 2 DP connections are available and I believe AMD to only offer a single connection.
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Found another user that was nice enough to post a screenshot. Problem is, that does not show what I expected.
I tested this myself a good while back with an AMD 6000 CPU and an older Win11 version without the USB4 panel.
And I recall reading over some threads here, where users reported situations, where their dock would not output a 2nd DP connection on FW13 AMD and took that as confirmation, that my experience must have been representative.
Has anybody with an AMD FW managed to extract 2 DP connections / tunnels through a single USB4 connection? Or is it more that Windows thinks there are 2 DP connections, but it never actually works?
To reliably show that AMD’s USB4 implementation can do that, we would need some kind of TB3 or TB4 dock, that internally uses both / can use both DP connections. Any TB4 hub (3 TB-outs) is the easiest, as if that drives more than 1 display, it is because there are 2 DP connections.
But docks with MST can still be used, if they give access to the 2nd connection, even if not intended.
For example, my Dell WD19TB dock uses only a single DP connection internally for the DP & HDMI outputs (using MST), which is why all of those also work on USB-C/DP Alt mode.
If any of those outputs are in use for 1 monitor, the TB-out on that dock can provide a 2nd DP connection if the host provides one (although it will be throttled, due to the dock prioritizing its main outputs, but it will still detect a monitor and allow to drive that at like FHD@60).
Just as a warning: The Lenovo TB4 dock is weird. While it’s TB-out it labeled TB and can do that, it is wired up in 2 different ways and can also be driven via MST on non-TB/USB4 hosts. So a 2nd display on that dock, even when using the TB-out would not be conclusive by itself and would require deeper investigation, which mode the dock internally chose to make that work.
Windows 11 also has a somewhat hidden debug option that can visualize the connections / tunnels through TB/USB4 in case someone is interested. This is behind the “Device Portal” under System>For Developers. Requires enabling Developer Mode, installing the Device Portal feature and rebooting after enabling it (can also be quickly disabled again just by flipping the Device Portal switch off). That hosts a website locally (by default only available from the device itself) that has a USB4 page that will sketch out the entire USB4/TB3 topology including active USB3, PCIe & DP tunnels.
(Here a screenshot of what that would show. near the root of the topology you can see the 2 DP tunnels and to which device/port they are routed to)
Edit: Oh and for my Linux friends: the “/sys/kernel/debug/dri/1/amdgpu_mst_topology” sysfile should report enough about the MST-topology to determine whether MST is involved or any given monitors are sharing a DP connection. Sadly I do not know better ways to debug how TB/USB4 uses DP tunnels.
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Hi @p_e
I bought an i-tec docking station (C31DUALKVMDOCKP) based on the message you posted last year, and I can confirm that it works very well, but strangely it doesn’t like my two screens (11080p & 11440p) and forces my 2k screen to be in 1080p. I’ve checked with my two connected laptops and it’s the same thing. I’d like to have a few details about your configuration, because apart from one of my screens, we’ve got the same thing, and I’d like to understand what I’ve missed.
My research hasn’t given me much information, my clues being a possible blockage due to the difference in screen resolution, a question of updating the Intel graphics driver or even the station firmware (i-tec having already mentioned on a post a problem already observed similar to mine on other models).
Here are a few details in case anyone else has an idea:
System: Ubuntu 23.04
Firmware: 03.04
GPU: Intel Graphics (ADL GT2)
Kernel: Linux 6.5.0-15-generic
Thank you in advance for your help 
Hi @Louis_BERTHET ,
I am still daily driving my dock with the same two monitors and still don’t have any issues.
As I mentioned my displays are two 2560x1440 monitors both running at 60Hz refresh rate (Maybe it is an issue with the refresh rate ? The dock lists it is only capable of doing two monitors at 60Hz). Both are from different manufacturers.
Out of curiosity I tried lowering the resolution of on one of the displays to 1080p, this works fine for me. The new resolution is only outputted to a single display, the other display remains at 1440p. So this should rule out the dock as a limiting factor.
I am currently on Fedora 39 with Kernel 6.6.14, but I have used Ubuntu before that (I daily drove it on 22.10 & 23.04 for a long time until the upgrade to 23.10 failed miserably and I decided to give Fedora a try).
On the Bios side (I have a 12th gen), I did start on 3.05 and recently directly upgraded to the 3.08 beta. For me that did not change anything with regards to the dock behavior.
Additionally I also always install the intel-media-driver, mostly to enable hardware acceleration in firefox.
Hi @p_e
First thank you very much for your reply 
I see, in the meantime I’ve upgraded to version 3.06 of the bios and I’ve totally reinstalled my ubuntu to the latest version (23.10), but still nothing. I keep having the impression of observing a bandwidth “limitation” for my screens through the dock or at PC level; when I unplug the 1080p screen, the other ends up with its 1440p at 60hz. I’m left with two choices:
- Install Intel Media Driver and hope it does something on the graphics side of the card.
- Check which standard the video stream is currently running under (despite my research on the subject, I still can’t tell whether the dock is running under usb-c, TB4 or USB4, as I can’t find any visual indicator in the OS to tell me).
If you have any ideas on the subject, I’d love to hear from you.
Unless I missed it, neither of you mentioned how the monitors are connected to the dock. Are you using an adapter to go from the DP on the dock to HDMI, perhaps? Since the dock is utilizing DisplayPort Alt mode, a passive DP to HDMI adapter would cause problems, for example. I’m also curious if the problematic monitor has ever worked with this dock, in any configuration with any computer. Apologies if I’m rehashing anything you’ve already discussed somewhere.
Thanks for the suggestion. I have directly connected one monitor via HDMI and the other via Displayport, no adapters or anything in between. Also I am simply using the USB-C cables that came with the dock.
I also don’t think that the intel driver will help. I did not have it installed on Fedora initially and the dock still worked. Otherwise, I am out of ideas by now and I guess you would have to contact the i-tec support
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I was actually using a DP → HDMI cable, but after exchanging it for a real DP it didn’t change a thing 
But yes, I tested these two cables with a single screen connected to the dock (the 1440p) and it worked very well, going up to 75hz (max 160 on Windows).
I think I’ll contact i-tec support and check with them. Thank you both for your help 
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I am also facing the issue of connectivity. Initially i thought it is the issue of upgradation of drivers. But after reading it i got to know that it has nothing to do with drivers. I was adding devices to play ea sports fc 24.
No, I did not even know it existed up until now
early report from FW16
On the first attempt, I was unable to get the Dell WD19TB (technically the upgraded version to TB4, which is the same as the WD22TB) to output video via the TB ports.
dual screen via the dock (the two DP ports) worked without issue so far, but triple display out via the dock will require some troubleshooting.
The workaround I used at first was to plug the HDMI for the 3rd monitor directly into the laptop, not the dock.
More to come.
I have the ANKER PowerExpan 13-in-1 USB-C Dock, listed as approved. I am not able to get the Ethernet passthrough or HDMI to work. I have Windows 11 and Ubuntu installed on a AMD Ryzen Framework 13. Any help or suggestions appreciated. I did update the drivers from Framework for the Ryzen.
I noticed that “CADUAL4KDOCK” is marked as “Unsupported” because, the laptop is not being charged - this docking station does NOT support PowerDelivery and will not charge any laptop.
Quick question: In my office I have this StarTech USB-C docking station which supports up to three 4k@60Hz monitors.
I preordered the Framework 16 (7840HS + gpu) and I am planning to use it with Artix Linux (Arch Linux w/o systemd) as my daily driver for gaming and (private) productivity. In the long run, I would like to swap my three monitors with one DQHD display (5120px1440p).
Now to my problem: DisplayLink drivers are a bit of a struggle with Artix. Theoretically speaking, will I be able to use one DQHD display via the docking station at >=60 Hz without drivers over DP-alt mode? I am not that savvy with displays and related hardware, but DQHD are fewer pixels as 4k which the docking station supports. So it should work out of the box, am I right?
Of course, I could just plug in the monitor directly into the laptop. However, I use my setup also to work with another laptop (Windows) my company provides and would like to just have to unplug/plug in one USB-C cable instead of several two times a day. But if I would have to buy another pricy docking station, I will stick with plugging multiple cables.
Thanks in advance!