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#1 2021-10-12 11:12:33

anahisa
Member
Registered: 2021-10-12
Posts: 5

[solved] Multihead secondary HDMI display initialises but no output

Hey there,

I'm having some issues displaying any kind of output to a secondary HDMI display.
Basically what will happen is that the additional monitor will detect input, turn on, and then time out.
The monitor of course works as normal in another OS such as Windows so I can rule out any kind of hardware issue.
What makes it weird is on a previous install (identical to current, arch xfce base) after waking up the system from sleep, I had a displays option prompt to extend, in which case I had functionality of the second monitor up until the system was rebooted. I have not been able to successfully recreate this ?

The system in question is a desktop with a GTX1060.
I'm running as basic and minimal as I can, and have only installed xfce4/nvidia/lightdm to test after the initial arch install.

Xrandr can see both displays;

HDMI-0 connected 2560x1440+2560+0 (normal left inverted right x axis y axis) 598mm x 336mm
   2560x1440    144.00*+ 119.99    59.95  
   1920x1080    143.99   119.88   100.00    60.00    60.00    59.94    50.00    29.97    25.00    23.98    60.00    50.04  
   1680x1050     59.95  
   1600x1200     60.00  
   1600x900      60.00  
   1440x900      59.89  
   1400x1050     59.98  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      59.94    50.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    72.81    59.94    59.93 

DP-4 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   2560x1440     59.95*+ 144.00   120.00    74.97  
   1920x1080     74.91    60.00    59.94    50.00  
   1680x1050     59.95  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x800      59.81  
   1280x720      60.00    59.94    50.00  
   1152x864      59.96  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93

As well as Xorg.0.log;
https://pastebin.com/Y3emzpPu

I've tried configuring in previous installs using nvidia-xconfig and generated config with nvidia-settings as well to no avail.

I want to hope it's something tiny that I'm missing but at this point I'm lost, so any guidance is greatly appreciated.

Cheers,
Ana

Last edited by anahisa (2021-10-13 08:15:47)

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#2 2021-10-12 11:44:45

seth
Member
Registered: 2012-09-03
Posts: 23,866

Re: [solved] Multihead secondary HDMI display initialises but no output

Does this work?

xrandr --output HDMI-0 --rate 60

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#3 2021-10-12 11:52:02

anahisa
Member
Registered: 2021-10-12
Posts: 5

Re: [solved] Multihead secondary HDMI display initialises but no output

seth wrote:

Does this work?

xrandr --output HDMI-0 --rate 60

Hey Seth,

Unfortunately not.
I'd tried other xrandr commands previously that I didn't note in the OP;

xrandr --DP-4 --auto --primary --output HDMI-0 --auto --right-of DP-4

wouldn't work for me either.

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#4 2021-10-12 11:57:09

seth
Member
Registered: 2012-09-03
Posts: 23,866

Re: [solved] Multihead secondary HDMI display initialises but no output

xrandr --output HDMI-0 --mode 1920x1080 --rate 60

(We're trying to significantly lower the signal here, also check "xrandr -q" on wthether the changes apply)

Is the output VRR capable?
https://wiki.archlinux.org/title/Variable_refresh_rate

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#5 2021-10-12 22:43:11

anahisa
Member
Registered: 2021-10-12
Posts: 5

Re: [solved] Multihead secondary HDMI display initialises but no output

The monitor in question (VX2758-2KP-MHD) is Freesync compatible, which doesn't really help.
It seems what you've given me is working though, I've definitely tried this in the past while scouring the forums but nonetheless I'm glad it's cooperating.


Initially tried

xrandr --output HDMI-0 --mode 1920x1080 --rate 60

,
As well as

xrandr --output HDMI-0 --mode 2560x1440 --rate 144

which has also worked.

Genuinely baffled but as long as it's working haha.

Thanks for your help, I appreciate it.

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#6 2021-10-13 00:56:48

anahisa
Member
Registered: 2021-10-12
Posts: 5

Re: [solved] Multihead secondary HDMI display initialises but no output

Interesting issue now though, it'll repeat the same thing on reboot;

I can get it to display again by using previous command

xrandr --output HDMI-0 --mode 1920x1080 --rate 60

first, however using --rate 144 first will not work.

So naturally in startup script I can't get it to output to 144 at all, and it ends up being a bit cumbersome hmm
I'm going to keep tinkering in the meantime, but do you potentially know any workaround for this?

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#7 2021-10-13 06:17:19

seth
Member
Registered: 2012-09-03
Posts: 23,866

Re: [solved] Multihead secondary HDMI display initialises but no output

I actually kinda expected that when seeing #5
Changing the modeline forth and back will trigger re-handshakes w/ the output after the initial one fails (the HDMI handshake is hyper-fragile because you must be prevented from stealing the well crafted pieces of art that are created by hollywahahah… *sigh*)
I guess switching to a different VT and back will have the same effect.

What's the initial constellation?
I guess both outputs are there while the system boots?
Do both monitors show output during the boot process?
How do you start X11?

As workaround, you could have a startup script that juggles the modes which would ideally happen *before* your DM/desktop session session (notably shell, WM and compositor) starts.
Do not fork the calls (ie. don't append an "&")

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#8 2021-10-13 08:15:14

anahisa
Member
Registered: 2021-10-12
Posts: 5

Re: [solved] Multihead secondary HDMI display initialises but no output

seth wrote:

As workaround, you could have a startup script that juggles the modes which would ideally happen *before* your DM/desktop session session (notably shell, WM and compositor) starts.
Do not fork the calls (ie. don't append an "&")

Gotcha.

I'm using lightdm, so I've got them running through a startup script, that seems to have done the trick.
Worst case, if it re-occurs, I know what to do; all in the fun of learning I guess smile

Again, thanks for your help, seems like we'll be all good from here!

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