3 Screen Set up issue

User Support General
1

i have a Linux Laptop + 2 extra monitors which are connected via a adapter - HDMI and when i 1st set up QubesOS and for a few days thereafter all works on the 3 screen config as should but then out of the blue i seem to of encountered a weird issue where as 1 of the monitors in particular has developed issues in that some Files and some Qubes when opened in the said monitor refuses any clicking into the file, icon, document, spreadsheet etc yet it will let me drag out the item from the monitor and place it in the other monitor and thus will let me work on it perfectly normal yet when i drag it back to the other monitor im somewhat restricted on what i can and cant do, however the offending monitor does let me fully use Qubes Manager and Qubes Apps in it fully without a glitch.
Yet KeepassXC, Files, Documents, Spreadsheets and such like all refuse to acknowledge anything other than allowing me to move the curser, grab the offending window and drag or press the x to close down the offending window.

If it helps any my monitor config arrangement is laptop bottom middle and the 2 xtra monitors directly above Laptop screen.

Please note that i run on a Linux approved Laptop and i have tried shutting down and restarting many-times and trying to alter then re-alter the Display config yet same result issue constantly there which i find so baffling mainly as it seems to be consistently selective as to what i can and cant do with that particular monitor… :face_with_monocle:

2
3

Thanks for that, ive read it and need to re-read many times to figure out how to construct a command to try, however i don’t know whats the command to know what ive already got as i would of thought to 1st find out what ive already got before i try and adjust it?
Also it was unclear as to what Terminal i use, i guess dom0?

Also with it working fine before and ive not changed anything i would of thought that couldn’t be the issue or maybe to much thinking from me…

4

By default, it is as much as needed for the current display and an additional full HD (FHD) display (1920Ă—1080 8 bit/channel RGBA).

Yes, in dom0.

5

When i go to top left Q icon i can not find anywhere “dom0” so how do i use dom0 Terminal if dom0 doesnt showup there please?

6

Q → Gear icon → Other → Xfce Terminal

7

Thats defo there i see it there now thanks to you, however how does one know thats dom0 as theres no reference to dom0?

8

Check the window title:

[Dom0] Terminal - user@dom0:~
9

Thanx :rofl:

10

I use multiple monitors.

A quick note that running “free -h” in the dom0 terminal can show you how much ram you have left (or running “top” in dom0).
Dom0 running out of ram, which causes the kernel to automatically kill a dom0 process is one way to get problem that happens randomly “out of the blue”
(multiple monitors can consume more dom0 memory over time, which is never given back)

(also, doing “sudo dmesg | grep -v audit” in dom0 terminal is one way to see if something was killed by the kernel recently)

11

Those commands seem very helpful although i dont understand what im looking at and if its good or bad nor what to do about it if its bad, would you be kind enough to let me know what you think if i input the Output for you please?
if so then please kindly advise me on how i C&P from Dom0 CLI as it wont let me, ive tried right clicking mouse which does nothing and ive tried ctrl c which also doesnt work?

Ill write out the Output below;
$ free -h

Mem Total: 2.6Gi Used: 963Mi Free: 940Mi Shared: 250Mi Buff/Cache: 776Mi Available: 1.4Gi

Swap Total: 3.9Gi Used: 0B Free: 3.9Gi

12
13

Regards the monitor adjustment in Qubes, i have studied it and the URL you kindly sent but i just cant seem to get the Command correct from reading the description for my situation and was wondering if you would be kind enough to help me understand better please?

i have 3 monitors in total including my laptop monitor, i went to DISPLAY and it shows me in the GUI all 3 monitor sizes which are as follows;
x2 External monitors at 1920 x 1080
x1 Laptop Monitor at 1920 x 1080

I opened up dom0 and have tried the following command to no avail;
$ qvm-features dom0 gui-videoram-min $(($1920 * $1080 * 4 / 1024))
i also tried;
$ qvm-features dom0 gui-videoram-min $((1920 + 1920 + 1920) x 1080 * 4 / 1024))

I am sure i am doing something silly or missing something easy but i just cant seem to grasp the command for 3 monitor set up, gee i am so so so much of a beginner here :flushed:

14

You can just run this command from the guide:

In the case of multiple display with different orientations or if you plug/unplug displays, the following code will set correct memory size using xrandr.

qvm-features dom0 gui-videoram-min $(xrandr --verbose | grep "Screen 0" | sed -e 's/.*current //' -e 's/\,.*//' | awk '{print $1*$3*4/1024}')

Or if you want to do it manually then connect all your displays and run this command in dom0:

xrandr --verbose | grep "Screen 0"

You’ll see the output like this:

Screen 0: minimum 320 x 200, current 1920 x 3240, maximum 16384 x 16384

Use the current values 1920 x 3240 for calculation:

qvm-features dom0 gui-videoram-min $((1920 * 3240 * 4 / 1024))

Restart the qubes after changing gui-videoram-min feature to apply the change.

1 Like
15

I have just tried to do it manually and i got a return of;
Screen 0: minimum 320 x 200, current 5760 x 1080, maximum 16384 x 16384
but i dont know which screen it is talking about nor how i get it sorted for all 3 screens so im thinking if i follow your instruction will it just be for the 1 monitor being screen 0 as when i go to the Displays in the GUI it doesnt state anywhere screen 0 only display 1, 2 and 3?

16

When you say i need to run the command does that mean i insert the word run before the text or simply copy and paste exactly the command stated as the command seems to have red parts and i dont know how to know if that means the red parts are for me to change to something specific to me or if the command is just to be copied and pasted exactly as is into dom0?

17

So i presume if i have it correct from what you say and i quoted above then my command for dom0 for all 3 monitors to be working would be;
$ qvm-features dom0 gui-videoram-min $((5760 * 1080 * 4 / 1024))

does this command look correct please?

if so then why i not see anything about all 3 monitors or is the numbers i see combining already all 3 monitors together, if so then why does it only state 1080 rather than say 1080x3 being “3240” and what does the 4 and the 1024 mean please?

18

Screen 0 here is a combination of all your monitors so use the size of the screen for VRAM calculation.

Copy&paste the command as it is, the colors here don’t mean anything. Just change the screen size values to your own.

Yes, that’s correct.

The number is already combined.
Your monitors layout on the screen is like this:

| monitor1 | monitor2 | monitor3 | 1080
    1920   +   1920   +   1920   = 5760

* 4 = 4 bytes = 8 bit/channel RGBA for each pixel
/ 1024 = convert from bytes to kilobytes

19

So i typed the said command into terminal Dom0 and i got nothing in return, i shut down all QubesOS and re-started it and i seem to still have the same issue in that 1 of the monitors wont let me click anything in it, so i opened up Dom0 CLi & typed
$ xrandr --verbose | grep “Screen 0”
and the return was the same as last time when i was expecting it to now say that the current screen was; 5760 somewhere it didnt, it stated the current was; 3840 x 2160 so not sure whats going on, i checked the command 4 times to ensure i didnt have any typo’s in it as i cant C&P to and from Dom0 CLI but im rather sure i got the command correct but no action :cry: im pulling my hair out but theres no emoji for that…

Do you think it could be that i unplug the monitors usbc adapter before shutting down and dont re-plug it back in until after the desktop has been re-loaded do you think?

20

Did you change the layout of your monitors?
You need to change gui-videoram-min if your monitor layout was changed.
If your current screen size is 3840 x 2160 that means that your current layout is:

    1920   +   1920     = 3840
| monitor1 | monitor2 | 1080 +
| monitor3 |            1080 = 2160