2 GPU system (GT 710 + GT 1030) with 4 monitors but only GT 710 recognised

Graphics / Linux Linux
1

My set up is a GT710 and GT1030 GPUs with four monitors ( 2 x Philips 27" and 2 x BenQ 24") Philips are cabled with DVI and BenQ are both HDMI

nvidia-settings can see all 4 monitors and I have arranged them into two screens (BenQ on top of Philips to mirror real world).

Currently, only the two monitors attached to the GT 710 are on and working whilst the GT 1030 does not appear to be driving anything.

Ubuntu additional drivers gui is ONLY picking up the GT 710 not both GPUs so I have only two out of the four monitors working and it’s driving me crazy!!

I have had all four working before on Ubuntu 20.04 but then I borked my system by installing Ubuntu Studio desktop on top of LTS and had reinstall - not worked since then.

xorg.conf (2.9 KB)

I’ve tried debian, Ubuntu 20.04 LTS and Ubuntu 20.10 but can’t get this working.
Currently lspci shows this:
25:00.0 VGA compatible controller: NVIDIA Corporation GK208B [GeForce GT 710] (rev a1)
25:00.1 Audio device: NVIDIA Corporation GK208 HDMI/DP Audio Controller (rev a1)
26:00.0 VGA compatible controller: NVIDIA Corporation GP108 [GeForce GT 1030] (rev a1)
26:00.1 Audio device: NVIDIA Corporation GP108 High Definition Audio Controller (rev a1)

nvidia-smi shows this:

nvidia-smi -l
Tue Mar 9 18:03:42 2021
±----------------------------------------------------------------------------+
| NVIDIA-SMI 460.39 Driver Version: 460.39 CUDA Version: 11.2 |
|-------------------------------±---------------------±---------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 GeForce GT 710 Off | 00000000:25:00.0 N/A | N/A |
| N/A 45C P8 N/A / N/A | 24MiB / 2002MiB | N/A Default |
| | | N/A |
±------------------------------±---------------------±---------------------+
| 1 GeForce GT 1030 Off | 00000000:26:00.0 On | N/A |
| 32% 37C P0 N/A / 30W | 184MiB / 1993MiB | 0% Default |
| | | N/A |
±------------------------------±---------------------±---------------------+

±----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 1 N/A N/A 1724 G /usr/lib/xorg/Xorg 95MiB |
| 1 N/A N/A 1856 G /usr/bin/gnome-shell 87MiB |
±----------------------------------------------------------------------------+

nvidia-bug-report.log.gz (522.5 KB)

2

Sounds to me you either want a xorg configured way, like the simple example here:
https://wiki.gentoo.org/wiki/Xorg/Multiple_monitors

Which means defining each monitor in a “Monitor” section. And then putting them into the “Device” sections accordingly.

Or use the nvidia way with the BaseMosaic option as described here:
https://download.nvidia.com/XFree86/Linux-x86_64/460.39/README/xconfigoptions.html

Your xorg.conf looks to me like both solutions halfway done.
I didn’t look further into your bugreport.log.

3

Thanks for you input - I’ll have a look at each solution and post results.

4

Hi,

This now resolved. I looked through various bits of documentation and posts online and one smacked me in the headpan - Cinnamon desktop does not support more than two monitors.

I swapped to xfce4 and voila! all four monitors sprang to life - I used the generated config from nvidia-settings and life is good.