Can I use dp splitter

Hello all,
I have 2 monitors and operate them with two computers.
One, with Windows, provides two hdmi and what remains are two dp ports, one for each monitor.
Daisy chaining impossible.

The second computer, tumbleweed shall operate on the dp ports.
Unfortunately, it has only hdmi port either…
So i bought adapter to dp and it works fine, but only on one monitor.
As splitters are expensive I ask whether it is possible to just add a splitter and have two monitors on dp then?
Is this supported by linux?
and how to configure?

All DP-HDMI converters I have experience with are one way only: DP output to HDMI input. IOW, standard DisplayPorts on displays must be fed by display port outputs, including MST splitters. DP MST splitters IME either work or not automatically. They need 1.2 or higher DP outputs to work at all. Reputedly, some USB-C outputs can serve as DP outputs to work with MST, but the only USB-C I have does not support video output.

Dual mode DP also exists for some displays to accept output from HDMI or DVI ports through inexpensive adapters. I believe this may be what enables some docking stations to work from an HDMI output and displays with DP inputs. The following is from using my Monoprice brand MST splitter:

# inxi -GSxxz
System:
  Kernel: 6.13.8-1-default arch: x86_64 bits: 64 compiler: gcc v: 14.2.1
  Desktop: TDE (Trinity) v: R14.1.3 tk: Qt v: 3.5.0 wm: Twin dm: 1: TDM
    2: XDM Distro: openSUSE Tumbleweed 20250418
Graphics:
  Device-1: Intel HD Graphics 630 vendor: ASUSTeK H110I-PLUS driver: i915
    v: kernel arch: Gen-9.5 ports: active: DP-3,DP-4,HDMI-A-3 empty: DP-1,
    DP-2, HDMI-A-1, HDMI-A-2 bus-ID: 00:02.0 chip-ID: 8086:5912
  Display: x11 server: X.Org v: 21.1.15 compositor: Twin v: 3.0 driver: X:
    loaded: modesetting unloaded: vesa alternate: fbdev,intel dri: iris
    gpu: i915 display-ID: :0 screens: 1
  Screen-1: 0 s-res: 3600x2640 s-dpi: 120
  Monitor-1: DP-3 mapped: DP-1-1 pos: top-left model: NEC EA243WM
    res: 1920x1200 hz: 60 dpi: 94 diag: 612mm (24.1")
  Monitor-2: DP-4 mapped: DP-1-2 pos: primary,bottom-l model: Acer K272HUL
    res: 2560x1440 hz: 60 dpi: 109 diag: 686mm (27")
  Monitor-3: HDMI-A-3 mapped: HDMI-3 pos: top-right model: Dell P2213
    res: 1680x1050 hz: 60 dpi: 90 diag: 558mm (22")
  API: EGL v: 1.5 platforms: device: 0 drv: iris device: 1 drv: swrast gbm:
    drv: iris surfaceless: drv: iris x11: drv: iris inactive: wayland
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 25.0.3 glx-v: 1.4
    direct-render: yes renderer: Mesa Intel HD Graphics 630 (KBL GT2)
    device-ID: 8086:5912
  API: Vulkan v: 1.4.309 surfaces: xcb,xlib device: 0 type: integrated-gpu
    driver: mesa intel device-ID: 8086:5912 device: 1 type: cpu
    driver: mesa llvmpipe device-ID: 10005:0000
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo gpu: gputop,
    intel_gpu_top, lsgpu x11: xdriinfo, xdpyinfo, xprop, xrandr
#

I did not find any device accepting hdmi and splitting into two DP, but it is definitively what would be best.
The problem is, I cannot really really your printout.

It seems as if there were 3 monitors…

Does the splitter occur also in the printout??

inxi -GSxxz
System:
  Kernel: 6.14.2-1-default arch: x86_64 bits: 64 compiler: gcc v: 14.2.1
  Desktop: KDE Plasma v: 6.3.4 tk: Qt v: N/A wm: kwin_x11 dm: SDDM
    Distro: openSUSE Tumbleweed 20250420
Graphics:
  Device-1: NVIDIA GF119 [GeForce GT 610] vendor: Micro-Star MSI
    driver: nvidia v: 390.157 arch: Fermi pcie: speed: 2.5 GT/s lanes: 4
    bus-ID: 01:00.0 chip-ID: 10de:104a
  Device-2: Advanced Micro Devices [AMD/ATI] Phoenix2 vendor: ASUSTeK
    driver: amdgpu v: kernel arch: RDNA-3 pcie: speed: 16 GT/s lanes: 16 ports:
    active: HDMI-A-1 empty: DP-1, DP-2, DP-3, DP-4, DP-5, Writeback-1
    bus-ID: 0b:00.0 chip-ID: 1002:15c8 temp: 49.0 C
  Device-3: HP HP 320 FHD Webcam driver: snd-usb-audio,uvcvideo type: USB
    rev: 2.0 speed: 480 Mb/s lanes: 1 bus-ID: 1-7.2:5 chip-ID: 03f0:654a
  Display: x11 server: X.Org v: 21.1.15 with: Xwayland v: 24.1.6
    compositor: kwin_x11 driver: X: loaded: modesetting unloaded: vesa
    alternate: fbdev dri: radeonsi gpu: amdgpu display-ID: :0 screens: 1
  Screen-1: 0 s-res: 2560x1440 s-dpi: 96
  Monitor-1: HDMI-A-1 mapped: HDMI-1 model: HP E27q G4 res: 2560x1440 hz: 60
    dpi: 109 diag: 685mm (27")
  API: EGL v: 1.5 platforms: gbm: drv: kms_swrast surfaceless: drv: radeonsi
    x11: drv: radeonsi inactive: wayland
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: mesa v: 25.0.4 note: incomplete
    (EGL sourced) renderer: llvmpipe (LLVM 20.1.3 256 bits), AMD Radeon
    Graphics (radeonsi phoenix2 LLVM 20.1.3 DRM 3.61 6.14.2-1-default)
  API: Vulkan v: 1.4.309 surfaces: xcb,xlib device: 0 type: integrated-gpu
    driver: N/A device-ID: 1002:15c8 device: 1 type: cpu driver: N/A
    device-ID: 10005:0000
  Info: Tools: api: eglinfo, glxinfo, vulkaninfo
    de: kscreen-console,kscreen-doctor gpu: amdgpu_top, nvidia-settings,
    nvidia-smi wl: wayland-info x11: xdpyinfo, xprop, xrandr

seems as if my graphic card has 4 DPs but i can see none…

That’s because there are: 2560x1440, 1920x1200 and 1680x1050.

Not explicitly, but wherever is seen in inxi output double-number-dashed DP- outputs, it’s indicative of splitting. So, you can see DP-1-1 connects to a 1920x1200 display and DP-1-2 connects to a 2560x1440 display. That iGPU shows as logically supporting 4 DP ports and 2 HDMI ports, but in fact the motherboard it’s on only has 1 DP output along with 2 HDMI outputs.

Inxi is showing your AMD GPU logically supports one HDMI port, 5 DisplayPorts, plus a writeback, but only sees attached a 2560x1440 display connected via HDMI. If there are no existing physical standard or mini DP outputs it could conceivably be indicative that a USB dock with DP outputs could be supported, and/or it could mean you have an APU that supports a motherboard with more graphics output ports than your current one has. inxi -GMSaz would more completely explain your graphics hardware/software configuration.

Lack of ports on Device-1 (NVidia dGPU) indicates its own outputs are not supported by the current configuration. IOW, to use the output ports on the NVidia you would need to couple it via SLI with another NVidia PCIe card, or in the BIOS change configuration to make the dGPU the primary GPU, which may disable the APU’s GPU function.

Interesting.
So the vendor of the splitter is not visible, but its placement.

inxi -GMSaz

yields

System:
  Kernel: 6.14.2-1-default arch: x86_64 bits: 64 compiler: gcc v: 14.2.1
    clocksource: tsc avail: hpet,acpi_pm
    parameters: BOOT_IMAGE=/boot/vmlinuz-6.14.2-1-default
    root=UUID=2c01224e-c0a4-4483-b1a2-45ae0755685a splash=silent
    mitigations=auto quiet security=apparmor nosimplefb=1
  Desktop: KDE Plasma v: 6.3.4 tk: Qt v: N/A info: frameworks v: 6.13.0
    wm: kwin_x11 tools: avail: xscreensaver vt: 2 dm: SDDM Distro: openSUSE
    Tumbleweed 20250420
Machine:
  Type: Desktop System: ASUS product: N/A v: N/A serial: N/A
  Mobo: ASUSTeK model: PRIME A620M-K v: Rev 1.xx serial: <filter>
    part-nu: SKU uuid: c4b7728f-7c40-120e-6287-107c61b1849f
    UEFI: American Megatrends v: 3033 date: 08/31/2024
Graphics:
  Device-1: NVIDIA GF119 [GeForce GT 610] vendor: Micro-Star MSI
    driver: nvidia v: 390.157 alternate: nouveau,nvidia_drm non-free:
    series: 390.xx+ status: legacy (EOL~2022-11-22) last: release: 390.157
    kernel: 6.0 xorg: 1.21 arch: Fermi code: GF1xx process: 40/28nm
    built: 2010-2016 pcie: gen: 1 speed: 2.5 GT/s lanes: 4 link-max: lanes: 16
    bus-ID: 01:00.0 chip-ID: 10de:104a class-ID: 0300
  Device-2: Advanced Micro Devices [AMD/ATI] Phoenix2 vendor: ASUSTeK
    driver: amdgpu v: kernel arch: RDNA-3 code: Phoenix process: TSMC n4 (4nm)
    built: 2023+ pcie: gen: 4 speed: 16 GT/s lanes: 16 ports: active: HDMI-A-1
    empty: DP-1, DP-2, DP-3, DP-4, DP-5, Writeback-1 bus-ID: 0b:00.0
    chip-ID: 1002:15c8 class-ID: 0300 temp: 49.0 C
  Device-3: HP HP 320 FHD Webcam driver: snd-usb-audio,uvcvideo type: USB
    rev: 2.0 speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 1-7.2:5
    chip-ID: 03f0:654a class-ID: 0102 serial: <filter>
  Display: x11 server: X.Org v: 21.1.15 with: Xwayland v: 24.1.6
    compositor: kwin_x11 driver: X: loaded: modesetting unloaded: vesa
    alternate: fbdev dri: radeonsi gpu: amdgpu display-ID: :0 screens: 1
  Screen-1: 0 s-res: 2560x1440 s-dpi: 96 s-size: 677x381mm (26.65x15.00")
    s-diag: 777mm (30.58")
  Monitor-1: HDMI-A-1 mapped: HDMI-1 model: HP E27q G4 serial: <filter>
    built: 2023 res: mode: 2560x1440 hz: 60 scale: 100% (1) dpi: 109 gamma: 1.2
    size: 597x336mm (23.5x13.23") diag: 685mm (27") ratio: 16:9 modes:
    max: 2560x1440 min: 720x400
  API: EGL v: 1.5 hw: drv: amd radeonsi platforms: gbm: drv: radeonsi
    surfaceless: drv: radeonsi x11: drv: radeonsi inactive: wayland
  API: OpenGL v: 4.6 vendor: mesa v: 25.0.4 note: incomplete (EGL sourced)
    renderer: AMD Radeon Graphics (radeonsi phoenix2 LLVM 20.1.3 DRM 3.61
    6.14.2-1-default)
  API: Vulkan v: 1.4.309 layers: 1 device: 0 type: integrated-gpu name: AMD
    Radeon Graphics (RADV PHOENIX2) driver: N/A device-ID: 1002:15c8
    surfaces: xcb,xlib device: 1 type: cpu name: llvmpipe (LLVM 20.1.3 256
    bits) driver: N/A device-ID: 10005:0000 surfaces: xcb,xlib
  Info: Tools: api: eglinfo, glxinfo, vulkaninfo
    de: kscreen-console,kscreen-doctor gpu: amdgpu_top, nvidia-settings,
    nvidia-smi wl: wayland-info x11: xdpyinfo, xprop, xrandr

I understand (roughly)… but i do not need the second card, do I?
It seems to me a worse card than the one on the board. Right?

Does active: HDMI-A-1 indicate that I connect the HDMI with some intermediate device? this could be my hmi to DP adapter?

If your motherboard has the GPU ports needed, then you should be best off removing the much older dGPU. Try running glmark2 before removing it to compare with running it again after removal. I’d expect your much newer AMD to do better than the old dGPU.

HDMI-A-1 is the kernel’s name for the port. X uses inexplicably different naming, HDMI-1 in your case.
Adapters are not explicitly noted, if at all. The output port is what is named, nothing beyond physical connector on motherboard or dGPU.

This image of outputs shows me you have one VGA port and one HDMI port on your motherboard. Many newer motherboards, like yours, have built-in adapters to convert a DisplayPort to a VGA output, which is why you don’t see VGA in inxi output. Clearly you do have VGA available as a second APU output, which according to this, your E27q G4 provides an input for. If you can’t get a USB dock with a DP output for full quality digital, the VGA might prove adequate to task without buying anything more than a dime-a-dozen VGA cable from a thrift store.

I am not sure whether I understand correctly…
You expect that the DP output is on an USB port?

You recommend me using the VGA output?
Because there is DP signal on it??

“Expect” is a strong word. I believe that new enough USB hardware is capable of carrying video when the associated hardware is otherwise capable of supporting it and wired up for the task. People with laptops connect docks with video outputs using USB-C ports, so I believe it may be possible with your standard USB 3.2 ports to do the same. I can’t promise. I’m only suggesting to investigate further, assuming VGA turns out to not be satisfactory to your requirements, and your dealer won’t accommodate an appropriate trade.

DP ports can be converted to provide VGA output via a converter built into a motherboard, which is what your PRIME A620M-K appears to have, same as my PRIME B250M-C. There is no other reason for that VGA port to be where it is, but it’s not because there is a DP signal; instead because of the converter, it’s an available VGA (analog, with no sound) output signal.