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I'm trying to install lxde desktop on a remote Ubuntu 20.04 server and VNC in.

When I use a ubuntu 19.10 server I have no problem:

#USING 19.10

sudo apt-get install -y lxde xorg lxdm  --no-install-recommends 
#or
sudo apt-get install -y lxde xorg lxdm

sudo reboot

Using VNC it works just fine to access the GUI in 19.10

enter image description here

#USING 20.04

sudo apt-get install -y lxde xorg lxdm  --no-install-recommends 
#or
sudo apt-get install -y lxde xorg lxdm
sudo reboot

Hangs here and retries in infinite loop in 20.04:

enter image description here

Can someone tell me what the difference is and help me solve this?

Neal Barsch
  • 116

2 Answers2

2

I had this problem when trying out LXQT on a virtual machine. The problem turned out to be I was missing the driver for the display.

I installed LXQT

apt-get install --no-install-recommends lxqt lubuntu-desktop

After a reboot, the terminal hung at the same spot as you. Accessing via a terminal (either ctrl-alt-f2 or use SSH) showed that SDDM was running, but there weren't any logs indicating why the graphics were not appearing. The lshw command helped me narrow down the issue by showing the display was UNCLAIMED

# lshw -C display
  *-display UNCLAIMED
       description: VGA compatible controller
       product: SVGA II Adapter
       vendor: VMware
...

In order to fix

apt-get install linux-modules-extra-$(uname -r)
reboot

Normally this package is already installed, but it is not installed when using the linux-virtual kernel package (as I am using). Other solutions I saw indicated other video driver issues can cause it

Andrew Lowther
  • 6,451
  • I think your answer may have worked, but now ubuntu I think has updated 20.04 to fix this bug so installing the modules-extra isn't necessary anymore. 20.04 now functions as 19.10 did. I'll give you the bounty anyway – Neal Barsch Jun 09 '20 at 05:25
  • Actually I found an old instance that hadnt been updated and your solution worked. – Neal Barsch Jun 09 '20 at 08:59
1

I had a similar issue with gdm3 when switched between operating system version, then I found this cool stuff for solving the problem Solution .

For resolve this Problem :
1. Editing the Configuration file of gdm
    1.vi /etc/gdm/custom.conf or nano or gedit (Any editor is fine)
    2.You will find a line this line #WaylandEnable=false
    3.Uncomment that line
    4.Reboot

Whole Configuration file looks like this.

[daemon]
WaylandEnable=false
DefaultSession=gnome-xorg.desktop

[security]
[xdmcp]
[chooser]

[debug]
#Enable=true

2.Installing lubuntu-desktop

sudo apt install -y lubuntu-desktop
sudo reboot

3.Editing Grub

Step 1: Editing Grub

When you boot your system, just stop at the Grub screen like the one below. If you don’t see this screen, keep holding Shift key at the boot time.

At this screen, press ‘E’ key to go into the editing mode. Edit Grub Menu to fix Ubuntu freezing at loginPress ‘E’ key

You should see some sort of code like the one below. You should focus on the line that starts with Linux. Editing grub to fix frozen boot issue with Ubuntu LinuxGo to line starting with Linux Step 2: Temporarily Modifying Linux kernel parameters in Grub

Remember, our problem is with the NVIDIA Graphics drivers. This incompatibility with open source version of NVIDIA drivers caused the issue so what we can do here is to disable these drivers.

Now, there are several ways you can try to disable these drivers. My favorite way is to disable all video/graphics card using nomodeset.

Just add the following text at the end of the line starting with Linux. You should be able to type normally. Just make sure that you are adding it at the end of the line.

nomodeset

Now your screen should look like this: Disabling NVIDIA Open Source graphics driversDisable graphics drivers by adding nomodeset to the kernel

Press Ctrl+X or F10 to save and exit. Now you’ll boot with the newly modified kernel parameters here. Explanation of what we did here (click to expand) Step 3: Make permanent changes in Grub

Warning!

In some cases, not using the graphics driver at all or switching to the open source driver may result in poor looking resolution. If that’s the case with you, try switching to proprietary driver as explained in alternate step 3 (next section).

Don’t be too happy yet just because you are able to login to your system now. What you did was temporary and the next time you boot into your system, your system will still freeze because it will still try to load the graphics drivers.

Does this mean you’ll always have to edit Kernel from the grub screen? Thankfully, the answer is no.

What you can do here to change the grub configuration so that the Linux kernel will not try to load the graphics driver before the display server.

To do that, open the terminal (use Ctrl+Alt+T shortcut) and then use the following command to open the grub configuration file in Gedit editor:

sudo gedit /etc/default/grub

You’ll have to use your password to open this file. Once you have the text file opened, look for the line that contains: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash".

Change this line to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

It should look something like this: Edit Grub To Fix Ubuntu Boot FreezeEdit Grub To Fix Ubuntu Boot Freeze

Save the file and update grub so that changes are taken into effect. Use this command:

sudo update-grub

Once it is complete, reboot your system and it should not freeze anymore.

4.Changing Default Driver Manager     Try installing lightdm or reinstalling gdm3

sudo apt-get install lightdm

or Xfce 4 

sudo apt-get install xubuntu-desktop.

try reinstall ubuntu desktop manager

sudo apt install --reinstall ubuntu-gnome-desktop

for reference:

Aravindha Hariharan
  • 126