Ubuntu 16.04 not detecting second monitor connected via VGA

Question

I recently bought an acer E 15 E5-575G-53VG laptop that has an nvidia geforce 940mx on board apart from the integrated graphics. I have two video ports, one HDMI, one VGA. I hook up one monitor with each port and it's working fine with Windows. However, in Ubuntu, it's not detecting my second monitor connected via VGA. I'm using NVIDIA's proprietary drivers. I've been trying many answers and none seem to work and I'm at a complete loss at where to start debugging. Any help would be much appreciated. Thanks!

Solution 1

Install arandr. Run that. Tell us if it sees vga device and can activate.

Another idea. run nvidia-settings and look for the prime setter. I do not see problem you describe so much when I specify intel as dominant.

Generally, I see thus much less often after upgrading kernel to 4.8. Problem was severe in 16,04. Am running the post 16.10 devel packages also for x11.

If you still struggle, may need fiddle your nvidia driver version. If you write back, give version numbers on everything I mention..

Solution 2

Go to Applications-->System Tools-->Administration there is the option Nvidia X Server settings. Here you can select another display.

Comments

[Arun Kumar Nagarajan]

Hi Paul, I installed and ran arandr, it displays eDP1 and HDMI1, the laptop screen and the monitor connected to the HDMI screen respectively. I also was fiddling around with the nvidia x server settings, however, setting intel or nvidia as dominant had no effect whatsoever on the detection. And yes, I am running Ubuntu 16.04 and the kernel version is 4.4. And if this could be of any help, s14.postimg.org/mq74licz5/… is what I see in additional driver section. Thanks much for the reply.

[Arun Kumar Nagarajan]

Schwesi, I'm using GNOME and couldn't see the mentioned settings! Could you please let me know if this is expected?

[Schwesi]

I think this link explains it rather well: linuxconfig.org/…

[Arun Kumar Nagarajan]

I've now updated Ubuntu to 16.10 and the kernel to 4.8. However, it's still not working!

[pauljohn32]

Hm, if arandr does not show the device, that definitely means it is not being detected deeper in the X11 server . I doubt this will work well without some old fashioned X11 configuration, the kind they don't want us to do anymore. Lets see if the simpler explanations apply first. DId you try disconnecting the HDMI monitor, plugging in the VGA, and then going through the old fashioned stuff to "turn on" the VGA? Recall that VGA port is dead by default on many laptops, there is a function key combination that brings it to life. used to be FN-F8 on most systems. Also see all "xdpyinfo | more".

[Arun Kumar Nagarajan]

Paul, yes, I tried that, but couldn't get it to work. However, I noticed one thing. when I use xdpyinfo, irrespective of whether i run the command with and without the external HDMI monitor connected, I get only 1 as the number of screens. The only difference is that the dimension changes from 1920x1080 to 3840x1080. Is this expected? Thanks a lot for your help.

[pauljohn32]

The one giant screen thing is saying it finds HDMI and welds it together with your display. We need to focus on VGA. Disconnect/Ignore the HDMI, question is whether VGA is ever detected. If you restart after connecting only VGA, and same problem exists, it means you have a deeper problem than Gnome config or such. It means you have X11 configuration to do. If you did not do it yet, it might help to, install "nvidia-settings". That may help to tell if the X server even sees the VGA device at all. But I'm thinking your VGA output is just OFF and you need to see how to turn it on

[Arun Kumar Nagarajan]

Hi paul, after a lot of failed attempts, I thought I'd try Fedora. I inserted the live usb and i could see all three monitors :) So I went ahead and installed it. However, there was some problem with GRUB so I thought i'd create a live USB with Ubuntu to fix the grub. It was then that I noticed that even when using Ubuntu in live USB, all the monitors were getting detected in Ubuntu as well. So I reinstalled Ubuntu, but, after restart, the problem came back. Then I reinstalled Ubuntu again, but this time, without downloading more updates during installation and it worked!

[pauljohn32]

Sometimes you hate computers, don't you?

[Arun Kumar Nagarajan]

hahaha :) yea, true :D