Nvidia Driver seems to be installed but no output (Ubuntu 22.10 on KVM/QEMU)

petreza · 10-24-2022, 05:25 PM

I have a freshly installed Ubuntu 22.10 virtual machine (KVM/QEMU) running with Nvidia T400 passthrough.
The driver seems to be properly installed - if I run the "Nvidia X Server Settings" app, the GPU is detected and I can see the GPU temperature and info about my monitor:

Code:

DP-1-0 - (SAMSUNG)

Also, xrandr --listproviders gives me

Code:

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x46 cap: 0x0 crtcs: 4 outputs: 4 associated providers: 0 name:qxl
Provider 1: id: 0x241 cap: 0x2, Sink Output crtcs: 4 outputs: 6 associated providers: 0 name:NVIDIA-G0

and nvidia-smi gives me:

Code:

$ nvidia-smi
Mon Oct 24 18:17:01 2022       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 515.65.01    Driver Version: 515.65.01    CUDA Version: 11.7     |
|-------------------------------+----------------------+----------------------+
| 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  NVIDIA T400         Off  | 00000000:0A:00.0 Off |                  N/A |
| 38%   40C    P8    N/A /  31W |      5MiB /  2048MiB |      0%      Default |
|                               |                      |                  N/A |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                                  |
|  GPU   GI   CI        PID   Type   Process name                  GPU Memory |
|        ID   ID                                                   Usage      |
|=============================================================================|
|    0   N/A  N/A      5026      G   /usr/lib/xorg/Xorg                  4MiB |
+-----------------------------------------------------------------------------+

yet I do not get any output - the monitor does not detect any signal. Also, xrandr does not show any DP-1-0:

Code:

$ xrandr
Screen 0: minimum 320 x 200, current 2560 x 1600, maximum 8192 x 8192
Virtual-1 connected primary 2560x1600+0+0 0mm x 0mm
   2560x1600     59.99*   59.97  
   1920x1440     60.00  
................................  
   720x480       59.94  
   640x480       59.94  
Virtual-2 disconnected
Virtual-3 disconnected
Virtual-4 disconnected

petreza · 10-30-2022, 04:32 AM

I can get it to work, if I disable QXL under "Video" in virt-manager ("None"), and then boot. This forces Ubuntu to use NVIDIA since it is the only GPU present.

Is there a way to force the use of a particular display without the removal of QXL from the system?