18.10 - External monitors not working

[RobertRozic]

Hello, At first i was using 18.04 and external monitors didn't work even after installing nvidia-390, new kernel etc. I switched to 18.10 and it started working ( after fresh install ). I was using 2 external monitors, one on HDMI and other one on type C connector. After i switched to intel profile using prime-select to save power since i was not using external monitors, then switched back to nvidia my external monitors stopped working.

I am on 4.20.10-042010-generic kernel and nvidia-415 drivers There is no xorg.conf in /etc/X11/

I solved it using lightdm display manager as suggested, but i am interested why it is not working with gdm3 since it used to work before.

Thank you

[kfechter]

After switching back to nvidia on gdm3, did you try logging out and back in or rebooting?

[RobertRozic]

Yes i did, even reboot... Nothing happened

[kfechter]

I have external monitors working on 18.04. I installed nvidia-driver-415 instead of 390, and have kernel 4.20 installed. It took a reboot after switching, and it bugged out for a second, but they seem to work now. There are probably some bugs in GDM around multi monitors.

[kfechter]

IIRC, several people also had issues with the 390 drivers and multi-monitors

[M-Abozaid]

I'm having the same Issue, my external display is not detected even with lightdm and nvidia-driver-415 I'm using kernel 4.20.10. I have a 1080ti

[kfechter]

sudo prime-select nvidia && sudo reboot worked for me when it wouldn't detect my monitor.

it could also be a bug in xorg or the nvidia drivers, or that combination of installed items on 18.10. I had way more issues with getting 18.10 to work properly, which is why the guide now focuses on 18.04.x LTS.

[M-Abozaid]

Prime profile is already set to nvidia, and I'm using ubuntu 18.04 LTS

[kfechter]

Is it throwing any errors in dmesg?

Without having any kind of errors logged, it's extremely difficult to pin down driver issues.

[M-Abozaid]

I'm sorry but how can I view dmesg :)

[kfechter]

open a terminal and run dmesg.

you can also pipe into grep if you want to look for specific text

for example dmesg | grep nvidia dmesg | grep prime

[kfechter]

I do not recall if dmesg requires sudo. I don't believe it does

[M-Abozaid]

dmesg | grep nvidia dmesg | grep prime both return nothing :|

[kfechter]

hmmm. that means that the nvidia drivers and prime aren't throwing any errors.

I hate it when there aren't errors, makes everything more difficult.

Did you upgrade the kernel before or after the nvidia drivers were installed?

[M-Abozaid]

What's frustrating is that it was working fine after installation

[M-Abozaid]

I updated to 4.20.11 and I didn't work since then I downgraded to 4.20.10 and still not working

[kfechter]

hmm. its possible that the nvidia module borked on dkms.

try to reinstall the nvidia drivers with the below command

sudo apt install --reinstall nvidia-driver-415 nvidia-prime

[kfechter]

I didn't realize 4.20.11 was out. It's possible that that version broke something as well. It's not entirely uncommon to see point releases of a kernel break something that worked previously. since ubuntu doesn't normally remove old kernel installs, you could also select the older kernel by pressing esc at the purple screen and selecting "Advanced options for ubuntu"

[M-Abozaid]

Yes I did that I even uninstalled 4.20.11 Didn't help BTW It was working earlier with nvidia-390

[M-Abozaid]

Thanks a lot for you help

[kfechter]

no problem. I switched back to windows temporarily, but I can try 18.04 again with 4.20.11 and see if I can reproduce.

[kfechter]

switching kernels is always risky, that's why my hope is that 18.04.3 will ship with a kernel that already has the module fix.

[M-Abozaid]

I was wondering why do you recommend nvidia-driver-415 despite according to this this it doesn't support gtx 1050ti

What am I missing?

[kfechter]

That's the quadro specific driver. the Linux 415 series nvidia driver supports nvidia GPUs from 600 series up to the new 20 Series RTX cards.

"GeForce 600/700/800/900/10 series cards works with 390.xx, 410.xx and 415.xx nVidia drivers"

[kfechter]

https://www.nvidia.com/download/driverResults.aspx/141300/en-us

[M-Abozaid]

Got it 😄 one thing I noticed though is that when I open Nvidia x server settings I don't see the multi-display settings anymore, it only shows the Prime profile options

[popvladaurel]

Hey, I can confirm that nvidia-driver-415 works fine with kernel 4.20.6. I'm running elementary OS 5.0 at the moment, but it's built on Ubuntu 18.04. Still have to reboot to switch between prime prime profiles though...

[M-Abozaid]

I've tried multiple kernels and this is how x server settings looks like

[RobertRozic]

I have external monitors working with 4.20.11 and lightdm + nvidia-415 With gdm3 it isn't working I am using 18.10 Also i just got notification that 4.20.12 is out, now i am afraid to try it

[kfechter]

@M-Abozaid That screenshot shows that it is in Intel mode. it won't show any of the nvidia settings other than prime profile if it is in power saving. if switching to nvidia and rebooting isn't helping, then something has gone wrong with the install and it is stuck in intel mode.

[kfechter]

I have multi display working with nvidia-driver-415 and kernel 4.20.12. however, I installed the driver after upgrading the kernel, so its possible that DKMS isn't working and the driver is breaking with the kernel upgrade.

[M-Abozaid]

I'm able to switch to Nvidia (performance mode) but it makes no difference

[kfechter]

something is corrupt on the install then. my guess is upgrading the kernel after the modules were installed put everything in a bad state.

[M-Abozaid]

I had to reinstall everything :(... it's working now with kernel 4.20.10, nvidia-driver-415, and gdm3 Thanks for your help

[RobertRozic]

Yeah, i do not want to update kernel to not break modules since it is working at the time. Hope this will get fixed in future.

[RobertRozic]

I decided to give it a shot, i installed newest kernel 4.20.13 and it is still working as it should with lightdm. 18.10, 4.20.13, nvidia-415. Connected 2 displays using type c and HDMI.

[kfechter]

Cool. Im updating the guide to not do the kernel upgrade part since that seems to cause all sorts of issues.

EDIT: Or at least splitting the ukuu stuff out and placing warnings on it.

[kfechter]

for anyone still having the issues, could you try the second solution in the accepted answer?

https://devtalk.nvidia.com/default/topic/1044770/hdmi-output-missing-in-xrandr-command-and-external-monitor-does-not-work/

[naaada06]

for anyone still having the issues, could you try the second solution in the accepted answer?

https://devtalk.nvidia.com/default/topic/1044770/hdmi-output-missing-in-xrandr-command-and-external-monitor-does-not-work/

same issue here on a fresh install of 18.04.3 with nvidia-430 drivers and solved with that! thanks!

[RobertRozic]

UPDATE

Right now i am using:

• Ubuntu 19.04
• 5.3.15 kernel
• Nvidia 440 drivers
• GMD3

External displays working correctly

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[stale[bot]]

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