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I have a Dell UP2414Q monitor from 2014 that is using two tiles. The left and right side are basically a separate monitor, and DisplayPort's Multi-Stream Transport sends a signal to both.

On Windows, this works out of the box.

On Linux, there are two problems. 1: Both halves are separate. Only one half has the task bar, and full-screening anything goes to one of the halves. And 2: The halves are swapped. Right half is left.

For nVidia, this fixed the two issues:

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"

    Option         "TwinView"
    Option         "TwinViewXineramaInfoOverride" "3840x2160+0+0"
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DP-0.9, DP-0.8"
    Option         "metamodes" "DP-0.8: 1920x2160 +1920+0, DP-0.9: 1920x2160 +0+0"
EndSection

Now I can't figure out how to do this on a new AMD Picasso Raven APU computer running the amdgpu driver. There is Xinerama, which is old. There is also this new "tiling" support for this specific case. I can't figure out how to use either.

How do I use my Dell UP2414Q with MST over DP on my _AMD Ryzen 5 3400G?

Specs:

  • Linux Mint 19.2
  • Cinnamon 4.2
  • Kernel 5.2.0
  • Radeon Vega Graphics
  • AMD/ATI Picasso
Redsandro
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1 Answers1

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As far as I know, MST is broken on the kernel layer for 5.1+ kernels bug. It's quite weird that it's working on your setup.

In userspace we have TILE property in xrandr and this bug and this First one is already fixed(at least in 5.3.0-rc3)

For Cinnamon, if gtk use xrandr monitors feature, than just make sure you have xf86-video-amdgpu-19.0.1 installed link

If not, you could try something like this barely working hack that I use for KDE:

xrandr --screen 0 --setmonitor DellUP2715K 5120/597x2880/336+0+0 DisplayPort-0,DisplayPort-1
xrandr --output DisplayPort-0 --mode 2560x2880
xrandr --output DisplayPort-1 --mode 2560x2880 --pos 0x0 --panning 5120x2880+0+0/0x0+2560+0/-2560/0/-2560/0

xrandr --fbmm 597x336

Just change values and put it in your xinitrc.d, and try some magic manipulations with your DM(like changing primary display).

UPD: 597x336 - dimensions of your screen in mm

Dan
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Dan
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  • Interesting. For me, 5.1 does not work, and 5.3 does not work. I need 5.2 with amdgpu 18.0.1. I'd like to try the `xrandr` commands. I imagine I need `1920x2160` in stead of `2560x2880`, but what are those `597` and `336` numbers? What do they do and where can I find the correct numbers for my monitor? – Redsandro Aug 19 '19 at 12:33