White noise/static with Quadro T2000 mobile and external monitor

bug still present in 5.8.0-55-lowlatency #62~20.04.1-Ubuntu , nvidia 460.84.

@amrits Any further guidance on an expected working configuration?

The 5.8 kernel has both monitors working (manual install of evdi from Added support for 5.10 by applying @abucodonosor's patch found in #234. by sickcodes · Pull Request #237 · DisplayLink/evdi · GitHub ) but severe corruption on the second monitor occurs when filling visual buffer of konsole (kde xterm)

A refinement. Doing some checking of logs and I came across this in :
grep -i --color memory /var/log/Xorg.0.log
[ 21957.531] (–) NVIDIA(0): Memory: 4194304 kBytes
[ 21957.757] (II) NVIDIA: Using 24576.00 MB of virtual memory for indirect memory
[ 21958.060] (==) NVIDIA(0): Disabling shared memory pixmaps
[260495.749] (WW) NVIDIA(0): Failed to allocate 3840x2160+0+0 head surface: out of memory.

Is this relevant?

Hi @amrits , it’s been a few months and we still have this problem.

Any further information on which combination of drivers and kernel solve this?

Bug still present in drivers 465.31 with kernel 5.8.0-55-lowlatency #62~20.04.1-Ubuntu SMP

did some digging over the weekend and found some more details.

I noticed that in the dithering section of nvidia settings, there were no values set for the 2nd monitor - perhaps this is an oversight?

I set the values to be the same as the first monitor controls->(dithering, auto, 8bpc).
The static corruption goes away now. However when we get corruption, it now flashes at approx 30hz (used my Pixel to slow motion and count). It is possible it is aliasing as monitors are 60Hz.

Does this help anyone isolate this problem? Clearly if parameters can change this , it suggests the bug is somewhere in the driver memory management, or something to do with the Displaylink

This is a business product, I really need it to work as such!!!

I solved the white noise by placing a DP-> HDMI adapter. See

I am using 2xDP , one of the monitors has HDMI (the one with the noise), I’ll see if I can get an HDMI cable (as monitor has native HDMI) and see if it solves this.

Nvidia needs to up their game with bug-fixes. This black hole for a business product is a problem.

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Ok I tried using an HDMI cable to the remote (2nd) monitor and it made it worse. Specifically the screen bottom left had bits of the left screen overlap, misaligned and also it was really bright.

Back on 2xDP - perhaps I need to find a decent adapter in case it’s a problem with HDMI cable.
This is an LG 4K monitor and also has UsbC - but the lenovo doesn’t support daisy chaining like Apple…

My monitors don’t have colordepth indications - is there an xrandr way of looking at this?

ok nvidia settings says both monitors are 24 bit, so must be something else. However, perhaps the DP->HDMI adapter is doing something? I ordered the same model, will report back.

I can confirm this works - I am surprised but it works. Using both Display ports on the lenovo docking station the second 4K screen is stable. A side point, I had to set the monitor to sRGB mode, otherwise it was super bright - I wonder if anyone knows the details of this subtlety.

@amrits @nvidia277 Could we have some feedback from Nvidia as to why this workaround is necessary. The exact same cable being used with this adapter does not work using HDMI from the docking station. If this really is a 30 bit limitation, perhaps prod lenovo…

In my case, I was able to compare the OSD info of monitors when windows(24bit) and linux(30bit) are booted.The monitors EDID report they can support 30bit, but I guess the nvidia driver doesn’t respect the bandwidth limts due the middlemen(dockingstation etc) - see also DeepColourDepthSupportPlan - Ubuntu Wiki
On Linux it has clearly shown 30bit, and nvidiasettings shows 24bit.

So, instead of the adapter, you can use custom edid (see my askubuntu post), it worked for me to limit it also and prevent the screen corruption.
But it is very unflexible because of my daily docking/undocking cycles with different monitors between home<->office1<->office2.

Anyway, I can’t use Linux due unreliable docking/undocking (sporadic X11 restart/crash after resume). Really sad, not able to use the expensive mobile RTX 5000 in a reliable way in Linux without X11 crashes. Leason learned ;-)

I don’t really have a problem with that, but I will say when they finally get Wayland working (hold’s breath), those should go away…

The lenovo firmware is actually quite good in the sense that it doesn’t care what you plug in - I also use a Mac Pro with the same monitors. It’s just a bit maddening that an expensive Graphics Card doesn’t know its drawing junk on the screen.

I did inspect the EDID, and there is no information regarding bit width.
I used the Nvidia tool to get the EDID as the linux packages can’t see the monitors via i2c.

I tried yesterday the 470.57.02 driver.
No whitenoise anymore, but I am not able to drive two screens anymore. Only one screen works (it uses 30bit Color Depth according to monitor OSD) and nvidia-settings reports 24bits

Hello!

Reporting that I have a possibly related issue with Lenovo P15 (Quadro T2000) and Samsung Odyssey G7 as external via HDMI on laptop itself (not docked). Just a single external screen, running extended desktop with external and internal display.

I have not ran into display corruption - at least yet - but connecting to the display is really hit and miss.
I have to unplug the hdmi from laptop, then keep the monitor “active” by going into OSD → source, replug HDMI to get a signal.

Resolution or display scaling changes usually result in lost signal too. Refresh rate changes don’t seem to cause issues though.
Issue happens regardless of 24-bit or 30-bit color mode.

For reference the display works flawlessly with my home desktop PC (DisplayPort) and it worked flawlessly with my older work laptop via HDMI too.
Display has newest 1011.0 firmware.

Using NVIDIA driver ver. 471.41 in Windows 10 x64 Enterprise 19042.1526

TL/DR: Try upgrading the dock firmware.

I have suffered from this bug for a while now, all the way up to the current driver 520.61.05 available at Index of /compute/cuda/repos/debian11/x86_64 … and I think I fixed my problem. My configuration:

Lenovo Thinkpad P1 Gen 2 + NVIDIA Quadro T2000
Lenovo Thinkpad Workstation Thunderbolt 3 Dock Gen 2
4k 60 Hz monitor connected via DisplayPort to either port in dock
Debian Linux 11 + NVIDIA driver 520.61.05

Turns out, upgrading the firmware of the dock did the trick for me. My dock had firmware 3.1.00 and the version published by Lenovo in March/April 2022 is 3.1.81… I needed to boot Windows to run the firmware update tool.

Good luck everybody.