*working with xrandr 1.5 not finding how to connect second or third gpu* ------------------------------ Greetings Running debian buster (testing) using lxqt. Have 3 nvidia 570 gpus and 4 1920x1080 monitors. Have had this system now for almost 5.5 years and have had it running the four monitors all that time. Updated to buster (new testing) and found that there were some issues with proprietary drivers nvidia 375.66 - - - was having one gpu halt and upon reboot things seemed to work again. The time between reboots was getting down to less than 12 hrs when I landed up with a system with corrupted networking on a reboot. So in the process of re-install I decided to try the Nouveau drivers instead. So now I have a one gpu 2 monitor system available. Got to very much like the four monitors for my work layout so I want the other two monitors working. Using xrandr I can see Provider 0,1 and 2. DVI-I-1 and DVI-I-2 are connected. DVI-I-2-5 and DVI-I-2-6 are listed as disconnected. I have been able to create a virtual screen of 3840 x 3000 which is how I had things before this reinstall using $xrandr --fb 3840x3000 . Tried $xrandr --setprovideroutputsource 1 0 no changes looked for pci addresses found 01:00.0. 02:00.0 and 03:00.0 Looked in the kernel log and all I can see is a error code of -19 (for both Provider 1 and 2) which, after a lot of digging, seems to be saying "no such device" Tried $ xrandr --addmode DVI-I-2-5 1920x1080 then DVI-I-2-5 still shows as disconnected but with a resolution of 1920x1080 60.00 Next I tried $ xrandr --output VGA-2 --mode 1920x1080 --pos 1280x1280 --rotate inverted result - - warning: output VGA-2 not found; ignoring It used to be that this setup happened in xorg.conf (and was a monolithic file), then things were changed to files placed in /etc/xorg.conf.d (as individual descriptions - - - ie. devices, monitors and AIUI screens) and in my system these kind of files are now in /etc/X11/Xsession.d but there aren't any to do with graphics issues. Any information I haven't provided that would help others help me? I can't find any guides on how to setup xrandr to use multiple gpus AND more than 2 or 3 monitors (usually from only 1 gpu). Most of the randr information I can find is for at newest randr 1.3 and I have 1.5. Randr 1.4 is where the multiple gpu option was introduced so it should be possible but . . . . I've found https://cgit.freedesktop.org/xorg/pr...oto-1.5.0#n160 likely everything I need is hidden in this file but for the life of me I can't figure out what commands to use. If I were an expert I wouldn't be asking but I'm not and there are no examples to follow (or try). Suggestions please? (Maybe do I have to go for newer proprietary drivers? (rather not I sort of like the no issues right now with Nouveau!) TIA Dee