Questions[nx](ubuntu)

Description: The screen (especially terminal programs such as Terminal and Terminator) do not refresh properly when using any kind of remote desktop. There is occasionally quite a long lag, for example, when typing into a terminal window. If I switch to nouveau driver the issue goes away completely. The issue appears with both nVidia 430 and 440 versions. Old drivers don't support RTX 20 cards so I can't for example try 390.

I tried different remote desktop servers such as the NX NoMachine, and VNC vine, as well as different clients on MacOS and Windows, I even tried TeamViewer, all behave the same.

I have reinstalled Ubuntu 18.04 and no change.

Both the server and client are connected to wired gigabit router.

I have a problem with nomachine NX-client in Ubuntu. It seems that the keymapping has a problem. For example, the arrow keys do not work (except for up key which opens printscreen!). I searched online and found several solutions. However none of them worked for me:

solution 1)

On the server, change System->Preferences->Keyboard->Layouts to “Evdev-managed keyboard”

The server that I log into has Centos 5.7 on it and I cannot find “Evdev-managed keyboard” layout in keyboard setting. I tried several other generic keyboard layouts with no success.

solution 2)

add the following lines to /etc/X11/xorg.conf:

Section "ServerFlags"
Option "AutoAddDevices" "false"
EndSection

I did it and my keyboard stopped working completely! I had to use the on-screen keyboard to remove this setting and get back to normal.

solution 3)

Run xmodmap -pke > localxmodmap locally

Copy the file to server as .Xmodmap

Run xmodmap ~/.Xmodmap from terminal.

which gives me a bunch of errors such as:

xmodmap:  /home/fzc23/.Xmodmap:60:  bad keysym name 'XF86Switch_VT_1' in keysym list

and doesn't work.

I do not know what else to do. I would appreciate if somebody could help me out.

BTW, the NX-client on windows connects to the same server with no keymapping problem so I believe this is a problem in Ubuntu and has nothing to do with the server side.

I am getting the following warning message from a new installation of Ubuntu 10.04 (server version) on an HP Proliant DL380 G5:

Your CPU appears to be lacking expected security protections.

  $ /usr/bin/check-bios-nx --verbose 

gives me:

"This CPU is family 6, model 15, and has NX capabilities but is unable to
use these protective features because the BIOS is configured to disable
the capability"

and:

$ grep ^flags /proc/cpuinfo | head -n1 | egrep --color=auto ' (pae|nx) '
gives me:
flags       : fpu vme de pse tsc msr *pae* .... 

The Security/CPUFeatures documentation here, states that, "the first flags line will include nx if the BIOS is not disabling the CPU feature, and the CPU is actually NX-capable"

To summarize so far, "nx" is not shown in the flags line from /proc/cpuinfo, whilst "pae", is... Is there any documentation available or is anyone able to recommend a procedure for installing the "-server or -generic-pae flavor of the 32bit kernel"... and/or how to make the necessary adjustments to the BIOS.

Many thanks for putting up with this rather unwieldy question!

I followed these instructions to configure natural scrolling for my normal ubuntu (11.04) desktop, and they worked just fine:

http://maketecheasier.com/reverse-mouse-scrolling-direction-in-ubuntu/2011/09/16

but those settings, even when I'm logged in as the same user through nxserver remotely don't apply. So I tried to adjust the scroll direction manually using xinput like so:

 xinput list 
"pointer"   id=0    [XPointer]
"keyboard"  id=1    [XKeyboard]

and then:

 xinput get-button-map 0
X Error of failed request:  XI_BadDevice (invalid Device parameter)
  Major opcode of failed request:  131 (XInputExtension)
  Minor opcode of failed request:  3 (X_OpenDevice)
  Device id in failed request: 0x0
  Serial number of failed request:  15
  Current serial number in output stream:  15

to see the current button map, trying to change the mapping with:

 xinput set-button-map "pointer" 1 2 3 5 4 6 7 8 9 10 11 12 13 14 15 16
X Error of failed request:  XI_BadDevice (invalid Device parameter)
  Major opcode of failed request:  131 (XInputExtension)
  Minor opcode of failed request:  3 (X_OpenDevice)
  Device id in failed request: 0x0
  Serial number of failed request:  15
  Current serial number in output stream:  15

results in the same error. Anyone know how to do this?

I've been reading about how the new Compiz-based Unity has issues with virtual box and what not.

Since NX effectively sets up a virtual interface/session, will Unity work within an NX server session?

Has anyone had any experience with this yet?