Hello everyone,
I have a Lenovo ThinkPad T480s laptop running Fedora 39 Kinoite. I would like to use it in a multi-display setup, so I am looking for a docking station. The laptop has a Thunderbolt 3 port. I have attached the details of my device at the end of the post.
People on Reddit are writing that "all Thunderbolt docking stations should work fine" and that's obviously not the case... I have this Dell Thunderbolt Dock (WD19TB) at home from work and the displays work when I plug it into the laptop but, for example, my mouse (connected via USB-A) doesn't work. When I connect it to the DELL laptop provided by the company, there are no problems at all.
Docking station requirements: Ethernet, 3x USB-A, 1x DisplayPort, 1x HDMI.
I have two 1080p displays: 75Hz and 165Hz. Obviously I'm not going to be playing any high-frame-rate games on this laptop, but even on a desktop it's sometimes nice to see a slightly higher refresh rate. So if it's possible, I'd like it to be able to display things above 60Hz...
I also have a Steam Deck OLED and would like to be able to use this dock with it.
I don't want to spend too much money on it. Do you have any experience in this area and can you help me choose?
I am from Poland if it helps in any way (maybe some brands are not available here).
LAPTOP DETAILS
Operating System: Fedora Linux 39
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11
Kernel Version: 6.6.6-200.fc39.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620
Manufacturer: LENOVO
Product Name: 20L8S0SA00
System Version: ThinkPad T480s
here's information I've pieced together from multiple sources. it's kinda ancient hardware and not many people are into supporting it, so information found online is often outdated and unreliable.
so, T480s are basically the same hardware as previous T470 with i5-7200u Kabylake chips, same HD620 graphics and are limited to two data lanes for USB Type-C for DP-Alt connections; newer gens have three. this means you can attach a 4K/60Hz display directly to the USB port and that works ~~it uses like 8 Gbps of the port's 10 Gbps~~ (inaccurate, explained in the link at the bottom). but, it won't work through a dock as the additional USB ports on it (as well as audio and LAN) exceed the throughput of them lanes. there's a table somewhere that lists how many lanes and Gpbs you need for different resolutions/frequencies, I'll try to find it; I've just memorized it for my use case.
now, T480s has TB3 (the USB Type-C farther away from the display, with the extended connector) that can do 40 Gbps, but my WD19 dock doesn't, that's why I was looking to upgrade to said WD19TB.
when you connect a TB dock to a TB laptop, a buncha things should happen. first off making sure TB security is off or permissive (in BIOS setup), because TB does DMA and that's needed for security purposes. it's possible you'd have to turn off SecureBoot in order for that to work. finally, granting TB permissions in the OS (Gnome Shell has a TB entry in settings, don't know how Plasma handles that). basically, if the OS doesn't ask you to grant permissions upon connecting, TB isn't used, you're just using USB 3.1 speeds and those aren't enough.
most of this is just speculation on my part, as I don't have first hand experience with TB because I can't afford to go around buying dock after dock until I find one that works; you're in an awesome position if you can try out all those things for free!
now, as to your specific conundrum, not sure those 100+ Hz display modes are supported at all but you'd have to research this for yourself. as a minimal first step I suggest you get a USB Type-C to DP cable or adapter, that supports DP-Alt and try the monitor directly.
edit: here's a bunch of useful info: https://old.reddit.com/r/thinkpad/wiki/newdocks
Thanks for the link! I hadn't come across this site before and it explains a lot.
For the Thunderbolt 3, I had the security level set to "User Authorization". I remember KDE Plasma showing me a popup asking for authorization for the Thunderbolt 3 port. I think I will just turn it off to make sure the docking station has the correct permissions.
Secure boot has already been disabled.
When I get home, I'll write about what I've achieved with this DELL docking station when I've finished checking it all out. But it looks like that these problems may be caused by the Thunderbolt implementation used in the laptop, as you wrote...
upon rereading that link, it seems no dock will work for my use case as all T models up to T14 Gen1 have this shitty thunderbolt implementation that won't allow me to use the maximum bandwidth of the TB link, i.e. 4K@60Hz and run all ports and LAN at the same time at full speed and use only one cable..
sucks for me, but money saved not chasing that goal, I guess.