Split Kernel Driver working... now I need to configure the monitors on second GPU. I'm lost!

I successfully got the split kernel driver method for displaying 2 different Nvidia GPUs accross 6 monitors as discussed in a link here:


After running:

xrandr --auto

The monitors on my second GPU came to life; however, now they’re all mirroring one of the monitors on my previous GPU (kind of… as only the cursor seems to be updating. They still show the old time when the monitors came on, windows are not updating, etc.) My question is, being fairly new to manually using xrandr like this… how do I configure those monitors not to mirror the other?

Display settings (using Mint Xfce) doesn’t show all monitors, so can’t configure them there. Thanks…

Update… got the monitor resolutions and orientations correct, using xrandr --output and (left-of, below, etc. commands). Mouse cursor moves where it’s supposed to between monitors; however, the monitors on the 2nd GPU are just blank and you can’t move windows or anything between them (again, just the cursor appears on the monitor when you move it to them).

Great! How did you manage to get both drivers loaded side-by-side? The last post sounds like a dual-screen setup, should be fixable. Care to share a nvidia-bug-report.log?

I followed the original advice that you posted the previous OP (that you linked), and it worked; however, the part here:

options nvidia NVreg_AssignGpus="0:03:00.0"

When I tried this before, I was using the BusID that was generated in the xorg.conf for the 1080 TI (which was 66:0:0, so I used 0:66:00.0).

I then realized when I ran this command:

lspci -v -d 10de:*

It listed my 1080 TI as 42:00.0. Once I changed the NVreg_AssignGpus to point to 0:42:00.0 it worked properly.

I’ll attach the nvidia-bug-report.log to this after I post it.

Actually, where do I find or generate that log? It’s not in my /var/log.

EDIT: Nvm… found out how to generate it. See attached.
nvidia-bug-report.log.gz (1.07 MB)

Please run nvidia-bug-report.sh as root and attach the resulting .gz file to your post.

Got it… attached it to the above post. Thanks!

It’s always confusing that the Xserver is expecting decimal values and everything else is working with hex.

Logs look good. What’s the output of xrandr --listproviders ?
xrandr --auto isn’t sufficient,

xrandr --setprovideroutputsource modesetting NVIDIA-0 && xrandr --auto

enables PRIME and then adds new monitors.

Providers: number : 2
Provider 0: id: 0x26b cap: 0x1, Source Output crtcs: 4 outputs: 7 associated providers: 1 name:NVIDIA-0
Provider 1: id: 0x48 cap: 0x2, Sink Output crtcs: 4 outputs: 5 associated providers: 1 name:modesetting

I’ll try that combined command and let you know after a reboot.

Unfortunately, running:

xrandr --setprovideroutputsource modesetting NVIDIA-0 && xrandr --auto

did nothing.

Alright… so now the general display settings in Mint Xfce shows all 6 monitors. I can arrange and set primary from there. Still having an issue w/ the monitors on my 2nd card acting weird (sometimes the background will draw, sometimes they’re blank, you still can’t drag windows to any of them; however, mouse cursor moves across them all normally).

Please try exchanging the xorg.conf block

Section "Device"
    Identifier     "Device1"
    Driver         "modesetting"
    Option         "AccelMethod" "none"
    BusID          "PCI:6:0:0"


Section "Device"
    Identifier     "Device1"
    Driver         "nouveau"
    BusID          "PCI:6:0:0"

One other observation… desktops on the 2nd GPU flicker on occasion when I move my mouse (regardless what monitor it’s currently on). It appears to be a PRIME Synchronization issue. Running the following command for each monitor on the 2nd GPU stopped the flicker:

xrandr --output <output name> --set "PRIME Synchronization" 1

Desktop wallpaper now shows properly on these monitors. Only thing left to do is get window forms to move over when I drag them.

EDIT: Alright, will do as you asked above. I posted this before see that. I’ll edit, reboot, and let you know.

Made your advised changes… xrandr --listproviders still looks good, and ran the combined command w/ xrandr --auto attached. Still the same issue where I left off… unable to move window forms across monitors.

Actually, I think something more serious going on here. The 2nd GPU isn’t drawing any forms. Right-clicking the desktops on those monitors don’t bring up a menu when they do on the others.

Got it to work!

In Section “ServerLayout” of the xorg.conf file… I had the wrong device set as Inactive (was the device for the 1080 TI… doh!).

Cool. Now I see it, too, you had duplicate modesetting sections. Sure was confusing the Xserver. Care to share a current xorg log and xorg.conf for posterity?

First off, want to thank you for your help, generix. Couldn’t have got it to work without out (and I’ve put in literally 100s of hours trying to get this to work before w/o any success). Secondly, we’re only 90% there. With both GPUs active w/ the 6 monitor under Mint Kfce, I had periodic UI freezes every 40-60 seconds that lasted 3-4 seconds each. Because of this, and knowing Cinnamon is even more of a headache when it comes to graphic driver issues (and I wanted to see if I could get this working from a fresh complete install)… I completely blew out my installation and attempted to install Mint Cinnamon from scratch, getting this to work there also. I did, successfully (going to put a step-by-step write-up how using our discussions); however, it’s still plagued by the periodic freezing (which only becomes present after the ‘modprobe nouveau’ which activates all the screens to come on). On reboot, this is the only command I have to enter to get it working once I initially get things setup (it’ll reset lightdm for me, etc. and take me back to a login screen where all six monitors work and are arranged properly). Not sure what is causing it, as I couldn’t find anything in the logs. There are still some minor glitches too, as sometimes objects being drawn flicker, etc. So, I’d say it’s a step in the right direction… but not usable quite yet.

I do have a question for you, generix. Under the ‘xrandr --listproviders’, I have the following for my 1080 TI:

Provider 0: id: 0x1b9 cap: 0x1, Source Output crtcs: 4 outputs: 7 associated providers: 0 name:NVIDIA-0

It says it has 7 outputs associated? How is that? I’m assuming the ‘Source Output crtcs’ are the actual number of ports on the back (3xdisplayport+1xHDMI)? Are each displayport capable of handling two outputs w/ the right adapter (only way I can get to 7 from 4 physical ports)?

Anyhow… I’ll provide the xorg.conf and log once I get back home this evening. Again, appreciate ya’.

Maybe setting some debug options for nouveau helps to find the cause for the intermittent frezzes. Have to look them up.
The 7 connectors comes from the fact that a DisplayPort connection can run either DP or TMDS(HDMI) transport. E.g. DP-0 is the HDMI part and DP-1 is the DP part of the same connector. The number of crts is the number of heads, i.e. the maximum number of (physical) monitors that the gpu can drive. So no adapter can lift that limit, you can only ever drive 4 monitors but have 7 possibilities to connect them.