Displays in my Thunderbolt dock are not detected

jchillerup · 2020-03-03 12:12:08

Hi everyone

I have a Thinkpad X1 Extreme Gen 2 with a thunderbolt dock, but the DisplayPort monitors connected don't seem to be detected by xrandr. I'm pretty sure the laptop has its displays wired to the Intel chip, and then the nVidia chip can use the shared framebuffer for accelerated graphics. I plan on using Bumblebee for this.

The monitors are not detected by xrandr, and they are not shown in the Displays tab in GNOME. They do work in Windows.

Here's what I have tried...

$ optirun nvidia-settings -c :8

gives me a window where it actually shows one of the monitors as connected — does that mean that it's actually the nVidia chip that's controlling the external outputs? — but so far I've been unable to get an image on the monitor.

$ intel-virtual-output

gives me the error: No VIRTUAL outputs on ":1".

I'm at loss as to how to debug this problem, as I have no experience with Thunderbolt, and DP on my previous Intel-based Thinkpads has just been working out of the box. I'd be very happy for any pointers that would get me closer to having the external monitors working (even without 3D accel would be good for a start). Thanks.

EDIT: Just booted into Windows, and it seems Windows also only detects one of the screens. So that's likely not a problem on the driver side in Arch.

Last edited by jchillerup (2020-03-03 12:38:28)

jchillerup · 2020-03-04 11:55:39

All right. I made a bit of progress since yesterday.

I removed Bumblebee and everything else I could think of that would control the power to my NVidia chip. Added the following modules to my mkinicpio.conf: nvidia nvidia_modeset nvidia_uvm nvidia_drm.

/etc/X11/xorg.conf.d/10-nvidia-drm-outputclass.conf

Section "OutputClass"
    Identifier "intel"
    MatchDriver "i915"
    Driver "modesetting"
EndSection

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    Option "PrimaryGPU" "yes"
    ModulePath "/usr/lib/nvidia/xorg"
    ModulePath "/usr/lib/xorg/modules"
EndSection

Note the ModulePath here...

/etc/X11/xorg.conf.d/20-intel.conf

#Section "Device"                            # This file does not exist by default
#    Identifier "intelgpu0"
#    Driver "intel"
#EndSection

(I'm trying to get stuff working using *only* the NVidia stuff at the moment...

/etc/X11/xorg.conf.d/20-nvidia.conf

Section "Device"
        Identifier "Nvidia Card"
        Driver "nvidia"
        VendorName "NVIDIA Corporation"
        BoardName "GeForce GTX 1050 Ti"
        BusID "PCI:1:0:0"
EndSection

~/.xinitrc

xrandr --setprovideroutputsource NVIDIA-0
xrandr --auto

xterm

Here's the Xorg.0.log trying to run Xorg (startx). It fails to find the nvidia module, even though it's specified in 10-nvidia-drm-outputclass.conf. As a super ugly attempt at fixing that I symlinked the .so into the other Xorg module directory, and then it finds it, but hangs my laptop screen. Switching to another TTY I was able to extract the logs.

The good news is that it detects my monitors. The bad news is that they show no image still... Can anybody see any problems in this setup (apart from the horrible symlink hack)?

jchillerup · 2020-03-04 12:10:20

I tried to run startx and moving to another TTY where I issued: DISPLAY=:0 xrandr:

Screen 0: minimum 8 x 8, current 7680 x 2160, maximum 32767 x 32767
DP-1.2 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
   3840x2160     60.00*+  30.00  
   2560x1440     59.95  
   1920x1080     60.00    59.94  
   1600x900      60.00  
   1280x1024     60.02  
   1280x800      59.81  
   1280x720      60.00    59.94  
   1152x864      59.96  
   1024x768      60.00  
   800x600       60.32  
   720x480       59.94  
   640x480       59.94    59.93  
DP-1.3 connected 3840x2160+3840+0 (normal left inverted right x axis y axis) 600mm x 340mm
   3840x2160     60.00*+  30.00  
   2560x1440     59.95  
   1920x1080     60.00    59.94  
   1600x900      60.00  
   1280x1024     60.02  
   1280x800      59.81  
   1280x720      60.00    59.94  
   1152x864      59.96  
   1024x768      60.00  
   800x600       60.32  
   720x480       59.94  
   640x480       59.94    59.93  
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)

So it looks like the driver thinks it's outputting something, but there is still no picture on my monitors

Running xrandr --listproviders (also with DISPLAY=:0) there is only the one NVIDIA-0 provider.

If I uncomment the configs in 20-intel.conf I get a desktop on my laptop screen, but only with the Intel provider.

Last edited by jchillerup (2020-03-04 12:29:37)

Durden · 2020-03-05 17:07:26

Do you have thunderbolt security enabled in bios? Some docks require permissions before a device will be allowed to work as a security measure against rogue devices being plugged in.

Arch Linux

#1 2020-03-03 12:12:08