External monitor with slow performance or not working at all

Hi,

I own a Lenovo P15 Gen 1 with RTX 4000 and have problems using an external monitor. I’m using the newest Fedora Silverblue version (kernel 5.9.14-200.fc33.x86_64) and Nvidia drivers (modinfo Nvidia version: 455.45.01). My 5k monitor is connected to the laptop using a thunderbolt 3 cable. I noticed that app which are displayed on the 4k display of my laptop are snappy whereas app displayed on my 5k monitor are displayed much more sluggish. The animations for example when clicking the „Show applications“ button are much smoother when displayed on the internal laptop monitor.

I did the following investigations:

  • The same apps running in a windows WSL2 and displayed via VcXsrv XServer are running smoothy without lag and without loud fan noise
  • Without Nvidia drivers and when using Wayland I have lots to problems. The external monitor is not displayed in the settings. With discrete graphics enabled I can not boot at all when the monitor is plugged in.
  • With Nvidia drivers, hybrid graphics settings in bios and X11 I can use my monitor with 5k resolution. But I have the performance problems described above. The fan noise is ok and not louder than using windows and wsl2
  • With Nvidia drivers, discrete graphics bios settings and X11 it I have other problems. The performance problems are gone, all is displayed smoothly. But there are other problems. Sometimes there is an offset between the two display halves in the middle of my external monitor. Every time there is a vertical line where the pixels are blurry. It is as if there is an offset too and the pixels color toggles between the color of the left the right side. It is not recognizable immediately but only if you look at a horizontal line in an application. But it is very annoying of there are two of these offsets (one in the middle and one blurry line on the right side).
  • Using discrete graphics if I close notebook so that only the external monitor is used, the problem with the pixel offset disappears. Better thann nothing, but I would really like to use the two displays (external + internal monitor)
  • Using hybrid graphics if I close notebook so that only the external monitor is used, the system gets unusable slow.

This drives me crazy. Because it works seamless when running the same apps in windows wsl2 with my monitor, I don’t want to buy new 4k monitors which might be more compatible with fedora. Any suggestions tipps how I can solve my problem?

Best regards
Meinert

P.S.: Posted the same question in the lenovo forum: https://forums.lenovo.com/t5/Fedora/External-monitor-with-slow-performance-or-not-working-at-all/m-p/5056029

Hi, check your 5k monitor refresh rate while it’s sluggish - xrandr shows supported and active modes. 60+ Hz should feel smooth.
Wayland is better suited for multiple displays with different pixel densities, I think, but it has some issues with nvidia proprietary drivers.
Try 450.80.02 driver, for some reason nvidia suggests 455 only for RTX 6000 - from Quadro RTX Series (Notebooks).

2 Likes

Thanks,

xrandr shows that 60+ Hz is used. But I‘ll try to install the other nvidia driver. I installed it by using the command

rpm-ostree install akmod-nvidia xorg-x11-drv-nvidia

and trusted that the correct version is installed :-(. There has to be a way to specify that the other driver branch is used instead other than download the rpm (which is not upgraded automatically). I‘ll search for that and give it a try the next days.

Thanks for the hint.

Regards
Meinert

There’s a minimal chance that your internal screen has higher refresh rate, 60Hz looks bad even next to 75Hz. Compare refresh rates in different scenarios.
Maybe system doesn’t deal well with two screens with different refresh rates? https://www.phoronix.com/scan.php?page=news_item&px=GNOME-Multi-Monitor-Vary-Hz this has already landed, but it only improved wayland (which has other issues).

You won’t get 450 from rpmfusion, they only package current and legacy driver, while nvidia has many branches and various recommendations. Before changing driver to the one from nvidia website make a BTRFS snapshot.

Good luck,
ozeszty

Hi,

as a former apple user I own the LG Ultrafine 5k which has a refresh rate of 60 Hz so that should not be the problem :-).

Unfortunately it seems as if it is just impossible to install specific nvidia driver versions in silverblue :-(. So I’ll have to stick with the one rpm-fusion installed or maybe try if it works with fedora workstation and the correct nvidia driver. Actually I would like to keep silverblue as my main distro and not switch to workstation because of its immutability. But with workstation it is at least easier to give the correct nvidia driver a try. If it the correct driver has the same problems, then I don’t have a reason to switch…

Best regards
Meinert

I installed Fedora workstation on an external SSD. After that I installed the nvidia driver 455.45.01 using the software dialog. The visual glitches haven’t appeared since then - even after lots of reboots. That’s strange because the same driver version is used. Anyway, seems as if I have to drop silverblue and switch to workstation or use silverblue and only have one monitor :-(.

Best regards

Meinert

I don’t have any experience with silverblue, I see that it requires adding kernel parameters manually, on Workstation and spins the installer does it automatically: https://rpmfusion.org/Howto/NVIDIA#Silverblue

I followed this guide Install Nvidia Drivers on Silverblue | by Egee | Medium and already have these kernel parameters :-(. I think I’ll just switch to workstation. Should have fewer problems using it because lenovo is testing this version with my notebook (thinkpad p15).

Originally I wanted to use silverblue because I like the immutability stuff - especially because it protects me against nightmares after upgrades. But with the btrfs filesystem I think it will be possiblle to rollback to an earlier snapshot easily in a near future release of fedora workstation too - similar to suse as boot entry. The tools I need for daily stuff can be installed in toolboxes and so won’t polute my workstation. So I think I’ll just switch to workstation.

The only thing is that now I have to figure out the preferred way to create btrfs snapshots manually until this functionality is provided by fedora workstation out of the box. But this problem should be solvable and might be easier than to figure out how to solve the nvidia (and other unknown silverblue) problems :-).

Thanks for your help
Meinert

1 Like

Good subject for separate topic. Good luck :slight_smile:

I just installed fedora silverblue again. The issue with my monitor disappeared. Often there are visual glitches after login, but unplugging my monitor up to two times solves the problems :-). Had such a visual glitch with windows yesterday too, so does not seem to be soley linux related. Even tough it happens not so often with windows.

So the problem is solved and I can keep silverblue :-).

Best regards

Meinert

1 Like

Great news!
Glitches might be related to gpu driver, but also Thunderbolt controller (check firmware updates), USB-C cable (try another one) or even monitor itself (even those now have firmware updates).
If, with everything up to date, it will still be happening on both Linux and Windows, it might be some hardware fault.