Xrandr can not found another Nvidia gpu NVS810 on ubuntu18.04

As the topic, I have two Nvidia graphic card ,one is GT710 ,another is NVS810. I connect three monitor, the nvs810 has two GPU1 GPU2. Then ,only GT710 caan found the monitor. I install the 430.50 driver and disable the nouveau driver.

matt@matt:/$ lspci | grep VGA01:00.0 VGA compatible controller: NVIDIA Corporation GK208B [GeForce GT 710] (rev a1)
04:00.0 VGA compatible controller: NVIDIA Corporation GM107GL [NVS 810] (rev a2)

And I set all device in xorg.conf. the private Nvidia driver can found them and when i use Xrandr to set multi-head, the xrandr can not found more providers , It only can found the GT710 and his output.

matt@matt:/$ Xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384VGA-0 disconnected (normal left inverted right x axis y axis)
DVI-D-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1440x900      74.98    59.89  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      60.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    72.81    59.94  
HDMI-0 disconnected (normal left inverted right x axis y axis)

Is anyone has the same problem? I’d appreciate if some one can give me some advice.

That doesn’t really work that way. You could enable Xinerama in xorg.conf to have an Xscreen spanning both gpus but I’d rather recommend removing the GT710 and connecting all monitors to the nvs810, possibly also enabling BaseMosaic.

Hi generix:
Thanks for your help. I test again with enbale Xinerama , and the GNOME doesn’t work correctly, but when i start the XFCE4, it’s expand large screnn , it 's work.
By the way, could you please tell me why that way is not work, is the X server driver bug or X server WM bug?


That’s a basic technical limitation of multi-gpu rendering, no bug. Think of moving a window from one monitor to the next, this means moving a window from one gpu to the other one, both have to render it and synchronize. This works even worse if the gpus are different models, losing hardware accel on at least one of them. Composition is also lost/not supported, that’s why gnome doesn’t work correctly.

Hi Generix:
Thank you very much for this explaination in detail and professional. I will accept your suggestion and connect all output to NVS810. Thank you.