Any Displayport 1.2 MST Hubs Known to Work With Linux/Mint?

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mattlach
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Any Displayport 1.2 MST Hubs Known to Work With Linux/Mint?

Post by mattlach » Mon Oct 15, 2018 11:00 pm

Hey all,

Essentially what I write in title.

I have one full sized DisplayPort 1.2 port on an AMD Ryzen 2400G based APU. I know it fully supports MST hubs under Windows, but I understand Linux can be pickier in this regard.

I experienced this first hand using a Startech dual port DP to DP MST hub, and some passive DP to DVI adapters. It looked like it would work, with the monitors being detected, but they were unable to display any image, with out of range errors.

I'm looking to connect three monitors to this one port, one 2560x1440 HDMI screen, and two older 1280x1024 DVI screens.

By what I'm gathering, part of my problem the first time around is that I used passive DP to DVI adapters, rather than active ones.

Maybe I could even use something like this, which is designed to take one DP port and turn it into three HDMI ports. It would stand to reason it is designed to overcome the passive adapter issue. Then since HDMI and DVI are essentially the same standard (with a different connector) I could use passive HDMI to DVI adapters from there.

Has anyone done this under Linux? What hardware did you use?

Much obliged,
Matt
Desktop: Intel i7-3930K@4.8Ghz, Asus P9X79 WS, 64GB DDR3-1866, 400GB Intel 750 SSD, Sound Blaster X-Fi Titanium HD, Nvidia Titan X (Pascal)
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AlbertP
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Re: Any Displayport 1.2 MST Hubs Known to Work With Linux/Mint?

Post by AlbertP » Thu Oct 18, 2018 5:49 am

MST typically works fine on Linux - depending on the GPU in your computer. I have an Intel GPU in my ThinkPad laptop and a ThinkPad USB-C Dock, which includes an MST hub. I have not connected a second monitor to it yet, but I know other people have done that with the same dock & GPU and that worked fine. At least, my computer detects two ports on the hub when I run 'xrandr -q'.

My monitor (Philips 240S1SB) uses a passive adapter to DVI as well, which is no problem. If the problem is not with your graphics driver, then it is possible that your computer or your MST hub is incompatible with DVI signals on the DP port. This is because it is not compulsory for DP devices to be compatible with DVI. In practice many of them are though. There is a logo for devices that are backwards compatible with HDMI and DVI: it is the "DP++" logo with two plus signs to the left of the DP logo.

To find out whether it's your GPU or the hub, please run the following commands while the monitors are connected (if possible) and post the output:

Code: Select all

inxi -Gx
xrandr -q
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