#1 2025-02-12 07:30:05

eightysixed

Member

From: USA

Registered: 2024-11-24

Posts: 58

_NET_WORKAREA & 3 Monitor Woes

I was originally just doing this because I got bored, but now it's starting to bother me, as I can't get it work.
3 monitors on  a GTX 750Ti (HDMI, VGA, and DVI).

They all power on and work as independent monitors, but there are bugs. The main screen, when you full-screen something, it snaps to about 66% of the screen, which is coincidentally odd as that's 1/3rd of 3 monitors. I have attached a screenshot of what it thinks "full screen" is - yet somehow the rest of the space is still usable (???) - see the second screenshot. I can even manually make things full-screen by click/dragging the corner of a window to expand.

I'm working with:

xrandr --output DVI-D-1 --primary --mode 1920x1080 --pos 0x0 \
       --output DVI-I-1 --mode 1920x1080 --pos 1920x0 \
       --output HDMI-1 --mode 1280x768 --pos 3840x0 &

Also there's this:

xrandr --listmonitors
Monitors: 3
 0: +*DVI-I-1 1920/598x1080/336+1920+0  DVI-I-1
 1: +DVI-D-1 1920/510x1080/287+0+0  DVI-D-1
 2: +HDMI-1 1280/477x768/268+3840+0  HDMI-1

It's misidentifying a VGA connection as a DVI-I-1 connection. Does that even matter, or is it just merely a label? If its the latter and doesn't have any consequences I surely don't care.

I'm not so sure those resolution numbers are correct, though? What's with the /<digits>?

Somehow, though, I think this has something to do with it..

xprop -root | grep _NET_WORKAREA
_NET_WORKAREA(CARDINAL) = 2560, 0, 2560, 1080

Thoughts?

Also odd is that if I "maximize" a window in the left monitor, it snaps to the main monitor in a single column. Screenshot also attached.

I think it comes down to _NET_WORKAREA, though.

Again, if I manually control window size and such, everything else is fine.
But that's too much of a pain when you have a bunch of windows open... it's just not realistic.

Any ideas/help would be greatly appreciated. Thanks!

(Click me!) Screenshots here...

e: I did find this thread (and even posted in it ), but between being super busy and then Super Bowl shenanigans over the weekend, I didn't really notice it wasn't fully working

Last edited by eightysixed (2025-02-12 07:57:18)

eightysixed

Member

From: USA

Registered: 2024-11-24

Posts: 58

Re: _NET_WORKAREA & 3 Monitor Woes

I completely removed nouveau (which turned out to be more of a headache than I expected) because it wasn't playing well existing alongside nvidia stuff, so I reinstalled Nvidia drivers and removed everything else as to remove any elements not needed.

sudo apt install --reinstall nvidia-driver nvidia-kernel-dkms nvidia-settings

Basically the same issues, but some noticeable changes:

• Insignia (right-HDMI) works as expected

• Dell (center-primary-VGA) thinks it's a DVI connection (I still don't know if this matters) and maximizes windows to only be 1240px wide and snaps to the right of the screen. (The rest of the screen is still ususable, see the Screenshots in the post above for reference)

• HP (left-DVI) still re-snaps and maximizes in a single column in the middle of the Dell (Primary). (Again, screenshot in post above)

The full output of xrandr is as follows:

xrandr
Screen 0: minimum 8 x 8, current 5200 x 1080, maximum 16384 x 16384
DVI-I-0 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 598mm x 336mm
   1920x1080     60.00*+
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected 1360x768+3840+0 (normal left inverted right x axis y axis) 477mm x 268mm
   1360x768      60.02*+
   1920x1080     59.94    60.05    60.00  
   1440x480      60.05  
   1280x768      59.99  
   1280x720      60.00    59.94  
   1024x768      60.00  
   800x600       60.32  
   720x480       59.94  
   640x480       59.94    59.93  
DVI-D-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 287mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1440x900      59.89  
   1280x1024     60.02  
   1280x720      60.00  
   1024x768      60.00  
   800x600       60.32  
   640x480       59.94  

Any ideas?

I'll eventually get it figured out, but I'm sort of stuck at the moment.

edit: waittttt, I didn't see that 4th display in the xrandr output. What is that doing there? I might be able to fix this super easy and over-thought it by a mile by never noticing that

Last edited by eightysixed (2025-02-12 22:31:46)

eightysixed

Member

From: USA

Registered: 2024-11-24

Posts: 58

Re: _NET_WORKAREA & 3 Monitor Woes

I really thought that xrandr --output DVI-I-1 --off would work. _NET_WORKAREA is still _NET_WORKAREA(CARDINAL) = 2600, 0, 2600, 1080. Okay? So I tried manually setting it -

wmctrl -r :ACTIVE: -b remove,maximized_vert,maximized_horz

.
Still no go.

Okay, lets force the workarea...

xrandr --fb 5200x1080

No go.

wmctrl -d
0  * DG: 5200x1080  VP: 0,0  WA: 2600,0 2600x1080  1

I don't understand.

I also tried forcing it adding <workarea>0 0 5200 1080</workarea> in the <desktop> section of bl-rc.xml.

Then to confirm:

wmctrl -d
_NET_WORKAREA(CARDINAL) = 2600, 0, 2600, 1080
0  * DG: 5200x1080  VP: 0,0  WA: 2600,0 2600x1080  1
1

I've tried forcing it from every angle I can think of..
What is going on?

Last edited by eightysixed (2025-02-12 22:32:46)

eightysixed

Member

From: USA

Registered: 2024-11-24

Posts: 58

Re: _NET_WORKAREA & 3 Monitor Woes

Well as it would turns out, I was trying to achieve the impossible.

Most GTX 750 Ti models can only support two active displays at the same time due to limitations in the Maxwell 1.0 architecture.
...
On many Nvidia cards from that generation, VGA and HDMI share the same output pathway, meaning you can use DVI + HDMI or DVI + VGA, but not all three

Oof. Good thing I spent two days on that. I ended up trying it on Windows and it flat out didn't work at all, so I knew something must be up. It's weird that it 97% works on Linux though. Part of me thinks if I kept messing with it long enough I could probably get it to work.

If anyone has any other ideas to try and force a proper WORKAREA I'll give it another shot, if not, this silly idea stays tabled