I use a Thinkpad P1 GEN2 (2019, 20QT000RGE) , with NVIDIA Quadro T1000 and a Think Pad Thunderbolt 3 Workstation Dock (40AN0230WW, mind it is the 'Workstation' Dock), on which I attach one or two external 4K-Monitors by either Display Port or HDMI.

This works fine with Windows 10, but with Linux I could not find a stable configuration where the screen does not gets black.

Has anybody this or a similar hardware-configuration running with Linux, and if yes, what is your software setup and configuration?

Any ideas what could be wrong or how to get closer to the issue?

I give details below: 

It happened rarley that the external monitor was shown, but after power-cycling it always stayed black and that is not reproducible. I never made it to show 2 monitors.
The external monitor is reported correctly to the operation system, likewise xrandr shows all information about the monitor correctly. One can configure the screens (resolution, multi-head with ...), one can move with the mouse (or move windows) to it and back and I could not find any error messages within Xorg.*.log . From the operating system perspective, everything looks perfect, just the screen stays black. I appears as if the monitor would be in powersave, but I even turned that of (in the Monitor, also by xset), and it happens with different monitors (different brands). When hot-plugging a monitor to the dock, usually the system load increases for a while (a minute) during which the system is extremly slow (mouse hard to move) and the 'top' command tells that nvidia-modeset is consuming ~90% of the CPU. 

I tried different things, without success:

• I use Ubuntu 18.04.03 , also tried 19.10, Mint 19.2.
• On Ubuntu 18.04 I tried with (standard) gdm (Gnome, no Wayland) , also I tried with Unity (since some report that gdm is an issue).
• I used different kernels, up to 5.3.11.
• I did a BIOS update on the Laptop to the (by now current) BIOS version 1.27 
• I use nvidia-driver-435 (by now most current for that hardware), also tried the nvidia-driver-440.
• For this dock (a 'Worksation' Dock), there is apparently no firmware update so far (just for the older ones). I just checked again there: https://pcsupport.lenovo.com/fi/en/products/accessory/docks/thunderbolt-3-workstation-dock/downloads/driver-list/ . There is just the update tool, which I did run (with Windows 10), but it says no updated available to me.
• It happens both with discrete graphics and hybrid graphics within the BIOS, so it seems not to be one of the Bumblebee/Prime issues which are widly discussed in this forum (which are about switching to hybrid), while I don't say it has nothing to do with Optimus. Anyway, the command 'prime-select query' outputs 'nvidia'.
• Using the HDMI-output directly on the Laptop, without the docking station sometimes works, but is not very stable, and sometimes it is black as well, also I'd like to use 2 Monitors.
• It makes no difference whether on the docking station the display port or the HDMI output is used.
• It makes no difference whether screens are extended or mirrored, the external is (almost) always black, and the internal (laptop) always shows a picture.
• Just to prevent questions: I attached the required two power supplies to the dock (attached are 230 W and 135W both at once).
• Everything else in the Dock (USB, Ethernet) seems to work.
• Everything else with the Thinkpad P1 works great with Ubuntu 18.04, but not having an external screen is a blocker.
• Two collegues of mine got a similar issue with exactly the same hardware and also Ubuntu 18.04: they do see some output, but a rectangular parts of the screen is scrambled with gray noise.

And a hint: The hardware is said to have the external output by thunderbolt wired to the nvidia chip, but I can not prove that, it is just something what I read several times somewhere.

Same Issue +1

My Envrioment

- ThinkPad Thunderbolt 3 Workstation Dock (230W)

( https://support.lenovo.com/us/en/solutions/pd500252 )

- ThinkPad X1 extreme gen2

( nvidia gtx 1650 )

- Windows10  & Linux Mint  Dual Boot

- bios version

➜ ~ fwupdmgr get-devices
ThinkPad X1E Gen2 Thunderbolt Controller
DeviceId: 426daa793d7f58eba9bd8d2dda27846519e57a21
Guid: afa98a84-bdd7-5c4d-8df0-a935055e0df9
Summary: Unmatched performance for high-speed I/O
Plugin: thunderbolt
Flags: internal|updatable|registered
Vendor: Lenovo
VendorId: TBT:0x0109
Version: 42.00
Icon: computer
Created: 2019-11-19

UEFI Device Firmware
DeviceId: 95426c1ada8b5820052af61f71e12134286adffb
Guid: 7ab93135-c544-4c88-ba2e-08ec6adb9e6f
Plugin: uefi
Flags: internal|updatable|require-ac|registered|needs-reboot
Version: 1.0.20483
VersionLowest: 0.0.1
Icon: audio-card
Created: 2019-11-19

UEFI Device Firmware
DeviceId: b649808587169ddcf6996a64fe99777e0b97c4d4
Guid: 466d3054-4e25-483c-96f0-d6c35e765042
Plugin: uefi
Flags: internal|updatable|require-ac|registered|needs-reboot
Version: 192.47.1524
VersionLowest: 0.0.1
Icon: audio-card
Created: 2019-11-19

UEFI Device Firmware
DeviceId: 3a7d0b9b370f21148edec601cee9ee5864d29fb9
Guid: 5aaaa50f-8348-43aa-befe-7fc4b9838ab5
Plugin: uefi
Flags: internal|updatable|require-ac|supported|registered|needs-reboot
Version: 0.1.19
VersionLowest: 0.1.19
Icon: audio-card
Created: 2019-11-19

20QVS06Y00 System Firmware
DeviceId: 105dc4287111ca23352a3b4759a602c10ad8bf88
Guid: 55d04ffc-714a-4457-b982-d244343e1958
Guid: 230c8b18-8d9b-53ec-838b-6cfc0383493a
Plugin: uefi
Flags: internal|updatable|require-ac|supported|registered|needs-reboot
Version: 0.1.27
VersionLowest: 0.1.0
Icon: computer
Created: 2019-11-19

- Linux distro & kernel info

➜ ~ neofetch --off
hdm@pc
------
OS: Linux Mint 19.2 Tina x86_64
Host: 20QVS06Y00 ThinkPad X1 Extreme 2nd
Kernel: 5.3.0-23-generic
Uptime: 2 hours, 1 min
Packages: 2250
Shell: zsh 5.4.2
Resolution: 1920x1080
DE: Cinnamon 4.2.4
WM: Mutter (Muffin)
WM Theme: Mint-Y-Dark (Mint-Y)
Theme: Mint-Y [GTK2/3]
Icons: Mint-Y [GTK2/3]
Terminal: gnome-terminal
CPU: Intel i7-9750H (12) @ 4.500GHz
GPU: Intel Integrated Graphics
GPU: NVIDIA NVIDIA Corporation Device 1f91
Memory: 3042MiB / 15724MiB

Thanks for the detailed reports - just to confirm we're looking into it.

Mark

+1, similar problem on a Thinkpad X1 Extreme 2019 and Arch Linux as OS.

I suspect that the fault is a combination of a kernel and nvidia problem. I remember at some point downgrading both to older versions and the problem was temporarily solved.

I have X1 Extreme Gen2 and Thunderbold 3 Workstation dock (230W) and my 2x 4K monitors works with a small problem.

I am experiencing some kind of noise on the screen. I tested this with other monitors, cables, etc. I experienced the same even with Dell WD19TB docking station.

Go to https://youtu.be/FnTWpv90DjE

Apparently there are even more users with this problem, it is also discussed in the Ask-Ubuntu Forum: https://askubuntu.com/questions/1183717/ubuntu-18-04-3-screen-scrambling-while-using-two-monitors .

I can reproduce the issue by connecting a monitor directly by a thunderbolt (say USB 3.1) Cable to an appropriate monitor (which has such an input), without that a docking station is used. It works with Windows 10 , but not with Linux. This proves it is (not only) an issue of the docking station, but with how the thunderbolt output is driven.

I got the issue with a P1 (Gen2) Laptop, while others use an X1 Extreme (Gen2). It is known that both Laptops are very similar by hardware, but apparently address different market segments.

On my TP X1E, dual monitors only work with dedicated nVidia Chip, not in hybrid or Intel mode. This mode can be selected in the nVidia driver.

Described my problem here

I think you are better with Ubuntu 19.10, as it brings a newer kernel.

Same problem here with a P53 with T2000 gfx and a TB3 workstation dock. It works without problem on Windows, but not on Linux. Two external 4k monitors work without problem when connected directly (not through the dock).

System is Ubuntu 19.10

Kernels 5.3.0-24, 5.3.15 and 5.4.2

Nvidia drivers 430, 435, 440

Bios settings does not seem to matter much. Tried with and without "bios assist mode". TB security switched off for testing (but that wasn't the problem anyway).

It also does not matter if discrete or hybrid graphics is selected in the BIOS. Only difference is that withOUT hybrid gfx

-- in text-mode (tty-console) -- the 4k monitors are in clone mode 4k@60Hz and display the VGA Text-console. With hybrid-graphics the kernel select the intel frame-buffer console und the external display stay black.

One more symptom: the NVidia driver tries to use 30Hz at most.

Concerning the _dual_ setup: also a single monitor connected through the dock just does not work reliably.

If someone has such a setup working it would be interesting to get the exact kernel and NVidia driver versions.

Thx. Claus

For me, the externel monitor does not work in hybrid or intel mode. Regadless if connected to dock or directly to my X1E. And even on nvidia mode, the monitor stays black during boot. But I will try to switch to discrete in BIOS as you described.

The HDMI and USB-C output are hard wired to the nvidia chip. So, if an external monitor is connected, it should switch to the nvidia graphics. This works in Windows but not yet in Linux. On Linux there is always a reboot required to switch graphics.

Some people say that they could get it working with Bmblebee, but it requires special configuration.

I also tried 5.4.4 Kernel on Ubuntu 19.10 which works stable but does ot change anything except slightly improves power consumption.