[Solved][MST]How to separate two screens using a single display port

Ekaradon · 2019-07-16 10:25:00

Hello,

I am using an asus ux501vw with two ultrasharp u2415 monitors and I have followed every step (at least I think) in the following tutorial but I still do not have two providers and I don't understand what I am missing. Can someone enlighten me please?

Only one monitor is detected

Here the logs:

# uname -a
Linux LAPTOP 5.2.0-arch2-1-ARCH #1 SMP PREEMPT Mon Jul 8 18:18:54 UTC 2019 x86_64 GNU/Linux

# sudo systemctl status displaylink.service
● displaylink.service - DisplayLink Manager Service
   Loaded: loaded (/usr/lib/systemd/system/displaylink.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-07-16 11:52:18 CEST; 26min ago
 Main PID: 680 (DisplayLinkMana)
    Tasks: 11 (limit: 4915)
   Memory: 8.4M
   CGroup: /system.slice/displaylink.service
           └─680 /usr/lib/displaylink/DisplayLinkManager

Jul 16 11:52:18 LAPTOP systemd[1]: Starting DisplayLink Manager Service...
Jul 16 11:52:18 LAPTOP systemd[1]: Started DisplayLink Manager Service.

# xrandr --listproviders                                 
Providers: number : 1
Provider 0: id: 0x46 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 3 outputs: 4 associated providers: 0 name:modesetting

# xrandr --prop                       
Screen 0: minimum 320 x 200, current 3840 x 1200, maximum 8192 x 8192
eDP-1 connected primary 1920x1080+0+120 (normal left inverted right x axis y axis) 344mm x 194mm
        EDID: 
                00ffffffffffff004c834c3200000000
                00170104952213780ace859e5b4c9426
                17505400000001010101010101010101
                010101010101dc3780a0703840403020
                250058c2100000190000000f00000000
                00000000001e82105200000000fe0053
                414d53554e470a2020202020000000fe
                00313536484c30312d3130340a2000cf
        scaling mode: Full aspect 
                supported: Full, Center, Full aspect
        max bpc: 12 
                range: (6, 12)
        Broadcast RGB: Automatic 
                supported: Automatic, Full, Limited 16:235
        link-status: Good 
                supported: Good, Bad
        CONNECTOR_ID: 85 
                supported: 85
        non-desktop: 0 
                range: (0, 1)
   1920x1080     60.10 +  60.01*   59.97    59.96    59.93  
   1680x1050     59.95    59.88  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.02  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1280x800      59.99    59.97    59.81    59.91  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   640x400       59.88    59.98  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
        EDID: 
                00ffffffffffff0010acb8a055554c32
                221c0104a53420783a0495a9554d9d26
                105054a54b00714f8180a940d1c0d100
                010101010101283c80a070b023403020
                360006442100001e000000ff00374d54
                303138384c324c55550a000000fc0044
                454c4c2055323431350a2020000000fd
                00313d1e5311000a20202020202001e3
                02031cf14f9005040302071601141f12
                132021222309070783010000023a8018
                71382d40582c450006442100001e011d
                8018711c1620582c250006442100009e
                011d007251d01e206e28550006442100
                001e8c0ad08a20e02d10103e96000644
                21000018000000000000000000000000
                0000000000000000000000000000000c
        Content Protection: Undesired 
                supported: Undesired, Desired, Enabled
        max bpc: 12 
                range: (6, 12)
        Broadcast RGB: Automatic 
                supported: Automatic, Full, Limited 16:235
        audio: auto 
                supported: force-dvi, off, auto, on
        link-status: Good 
                supported: Good, Bad
        CONNECTOR_ID: 91 
                supported: 91
        non-desktop: 0 
                range: (0, 1)
   1920x1200     59.95*+
   1920x1080     60.00    60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1920x1080i    60.00    60.00    50.00    59.94  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1280x720      60.00    60.00    50.00    59.94  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    60.00    59.94    59.94    59.94  
   640x480       75.00    60.00    59.94    59.94  
   720x400       70.08  
HDMI-1 disconnected (normal left inverted right x axis y axis)
        Content Protection: Undesired 
                supported: Undesired, Desired, Enabled
        max bpc: 12 
                range: (8, 12)
        content type: No Data 
                supported: No Data, Graphics, Photo, Cinema, Game
        Colorspace: Default 
                supported: Default, SMPTE_170M_YCC, BT709_YCC, XVYCC_601, XVYCC_709, SYCC_601, opYCC_601, opRGB, BT2020_CYCC, BT2020_RGB, BT2020_YCC, DCI-P3_RGB_D65, DCI-P3_RGB_Theater
        aspect ratio: Automatic 
                supported: Automatic, 4:3, 16:9
        Broadcast RGB: Automatic 
                supported: Automatic, Full, Limited 16:235
        audio: auto 
                supported: force-dvi, off, auto, on
        link-status: Good 
                supported: Good, Bad
        CONNECTOR_ID: 98 
                supported: 98
        non-desktop: 0 
                range: (0, 1)
DP-2 disconnected (normal left inverted right x axis y axis)
        Content Protection: Undesired 
                supported: Undesired, Desired, Enabled
        max bpc: 12 
                range: (6, 12)
        Broadcast RGB: Automatic 
                supported: Automatic, Full, Limited 16:235
        audio: auto 
                supported: force-dvi, off, auto, on
        link-status: Good 
                supported: Good, Bad
        CONNECTOR_ID: 105 
                supported: 105
        non-desktop: 0 
                range: (0, 1)

Furthermore, I don't understand what is DP-2 here, I am quite certain I don't have two display ports.

Thank you for any help you can provide!

Last edited by Ekaradon (2019-07-16 13:56:44)

Ropid · 2019-07-16 11:30:09

What is the concrete result you want to see? How are things working right now and what do you dislike about that?

Are you perhaps currently confusing "DisplayLink" and "DisplayPort"? The two are totally different things.

This "DisplayLink" thing you linked to is basically an external graphics card. That shouldn't be relevant to you. It's about a totally different type of product, not something that applies to your Dell U2415. Your Dell U2415 is a normal monitor and is driven by your normal graphics card.

In the output of "xrandr --listproviders", that second provider shows up with DisplayLink because DisplayLink is an external graphics card.

About why you see DP-1 and DP-2, I think that's because with one single DisplayPort connection you can drive more than one monitor through a "daisy chain" setup. One cable goes from your graphics card to one monitor, and then another cable goes from that monitor to a second monitor.

Last edited by Ropid (2019-07-16 11:32:36)

Ekaradon · 2019-07-16 11:50:07

I have this daisy chain setup. My first monitor has an DP output on my second monitor. My two monitors are active but they show the very same display. I want to break outputs between my two monitors.

I want my second monitor to be considered as another screen where I can put some stuff separated from my first monitor and my laptop screen.

Several resources pointed to the use of DisplayLink for MST but maybe I misunderstood the documentation. I have seen people talking about having DP 0.8 and DP 0.1, things like that and I believed that was the way to do it.

Ropid · 2019-07-16 12:12:59

Did you enable MST or "DisplayPort 1.2" in the menu of the first monitor?

Ekaradon · 2019-07-16 12:36:41

Ok that was the missing step. Huge thanks to you!

However I still have something really weird with my computer. When the DP is connected, I got this error when starting my computer:

[  196.406229] ACPI Error: Aborting method \_GPE._L69 due to previous error (AE_NOT_FOUND) (20190509/psparse-529)
[  196.406232] ACPI Error: AE_NOT_FOUND, while evaluating GPE method [_L69] (20190509/evgpe-505)
[  196.406810] ACPI BIOS Error (bug): Could not resolve symbol [\_GPE._L69.D1F0], AE_NOT_FOUND (20190509/psargs-330)
...
[  196.616715] ACPI BIOS Error (bug): Could not resolve symbol [\_GPE._L69.D1F0], AE_NOT_FOUND (20190509/psargs-330)
[  196.616717] ACPI Error: Aborting method \_GPE._L69 due to previous error (AE_NOT_FOUND) (20190509/psparse-529)
[  196.616720] ACPI Error: AE_NOT_FOUND, while evaluating GPE method [_L69] (20190509/evgpe-505)

I have seen report of this bug for the kernel 4.19 but I am already on 5.2 so I don't know whether it is normal. It does not block anything except making it impossible to read the output of dmesg.
When I remove the display port I do not have anymore this strange error.

V1del · 2019-07-16 13:08:17

These are usually to indicate a bug in your ACPI implementation, if you don't notice anything not working they are safe to ignore, if you want to actively do something against it you will want to try and apply a firmware/BIOS/UEFI update and hope your vendor fixed the issue.

Ekaradon · 2019-07-16 13:55:54

Ok thanks V1del! I will mark the topic as solved.

Arch Linux

#1 2019-07-16 10:25:00

[Solved][MST]How to separate two screens using a single display port

#2 2019-07-16 11:30:09

Re: [Solved][MST]How to separate two screens using a single display port

#3 2019-07-16 11:50:07

Re: [Solved][MST]How to separate two screens using a single display port

#4 2019-07-16 12:12:59

Re: [Solved][MST]How to separate two screens using a single display port

#5 2019-07-16 12:36:41

Re: [Solved][MST]How to separate two screens using a single display port

#6 2019-07-16 13:08:17

Re: [Solved][MST]How to separate two screens using a single display port

#7 2019-07-16 13:55:54

Re: [Solved][MST]How to separate two screens using a single display port

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