Hi,
I have a problem similar to
https://forums.developer.nvidia.com/t/ubuntu-20-04-second-monitor-doesnt-work-ubuntu-and-nvidia-settings-detects-it/124380
I have a Asus laptop running ubuntu 20.04 with Intel CPU (Intel® Core™ i7-3630QM CPU @ 2.40GHz × 8) and Nvidia GPU (GeForce GT 635M/PCIe/SSE2 / GeForce GT 635M/PCIe/SSE2)
There is a VGA output (with a HP monitor) and a HDMI output (with a Dell monitor)
I can’t get the 3 monitors displaying at the same time, It’s either the builtin monitor and 1 external, either the 2 externals (if I use the display mode “external only”)
When I switch to the Intel GPU (motherboard instead of the Nvidia), in the settings I get the 3 monitors but one is black
I tried the commands from the topic above and also to change the modset to 0, always rebooting between but nothing work
I attached 3 nvidia bug reports, with only VGA plugged in, only HDMI plugged in and both plugged in
Thank you in advance for your help
nvidia-bug-report-390-only-vga-log-gz (193.9 KB)
nvidia-bug-report-390-only-hdmi-log (202.9 KB)
nvidia-bug-report-390-both-hdmi-vga-log-gz (198.6 KB)
All your connectors are routed to the intel igpu, the nvidia gpu has none so fiddling with it won’t help.
The intel igpu is a HD4000, which is a bit limited. While it supports up to 3 monitor in theory, it only has two clocksources, meaning it only supports 3 monitors if two of them use the same type of connector so one clocksource can be shared. Your notebook uses three different monitor connections (LVDS+HDMI+VGA) so only two of them will ever work at the same time.
A while ago, around march 2020 during the pandemic outbreak, the 3 screens were working at the same time
At the time I just plugged and played
The only things which has changed are the OS (I upgraded from ubuntu 16.xx or 18.xx to 20.04) and probably the drivers
Might be. You would have to test with an older kernel and then check with the i915 devs whether this was disabled.