Let me preface this post by saying that I know about vncserver on the n800, vncserver on the desktop and RDP. All work fine to and from n800 and desktop, but I'd like a single app to be remotely displayed

I'd like to forward an X11 app on the n800 to my local X server on my desktop. I've set up OpenSSH, made sure that X forwarding is on in /etc/ssh/sshd_config, and that an XDisplayOffset of 10 is set, and restarted the ssh server. I then ssh -X user@n800, but my $DISPLAY variable on the n800 is still 0.0, rather than 10.0, as it should be. Manually doing an export DISPLAY=':10.0' doesn't work either, nothing displays on my local X server.

The other way around (ssh -X from n800 to desktop) and then running an app works fine. The DISPLAY variable (on desktop at that point) is properly set to 10.0, and I've compared the sshd_config files from n800 and desktop line-by-line, and they're identical for everything that should affect TCP and X forwarding.

Is this a limitation with Matchbox and Hildon, or am I doing something stupid here? As I say, I know how to forward X connections over SSH normally, but this isn't working.

I can't even do "normal" (=non-SSH'ed) forwarding from the 770 to my desktop. It seems the applications on the 770 just ignore $DISPLAY

Yeah, that's my take on it, too. Even if $DISPLAY is set, nothing happens - the app never loads, and I never get a prompt back w/o Ctrl+C

mhm.... here the application does load/run, only it shows up on the 770 and not on the PC specified via DISPLAY. strange thing is I dont even get errors about not being able to connect to the display etc. ...

Little more testing.... It seems to depend which app it is. If I run vncviewer, gpe-calendar, pwsafe, fmradio, and most others, they launch and display on the n800 (this is with ssh -X, and DISPLAY still as 0.0).

browser and mediaplayer-ui, on the other hand, don't launch, and just drop back to a shell.

Now, after manually setting $DISPLAY to 10.0 (export DISPLAY=':10.0') during the same SSH session, fmradio fails with Gtk - cannot open display:, as do pwsafe and gpe-calendar.

Vncviewer just returns to a prompt, no error. The browser and mediaplayer-ui just return to a prompt also, no error.

So, it appears that $DISPLAY is honored, at least by most apps, but something else is going on to prevent them from using it.

Edit: This is all as user, no "sudo su" or ssh -X root@n800 that could be confounding.

I'm not sure... Try the following:

On your GNU/Linux desktop PC, type
DISPLAY=10.0.0.126:0; xterm; echo $DISPLAY
(with 10.0.0.126 being a non-existent IP-address)

The output will be something like:
xterm Xt error: Can't open display: 10.0.0.126:0
10.0.0.126:0

Which tells me that xterm tries to open the display.

Now, on a N800 or 770, do the same (do it on the device itself, dont ssh into the tablet):
DISPLAY=10.0.0.126:0; /usr/bin/osso-xterm; echo $DISPLAY

Again, 10.0.0.126 doesn't exist. What happens is that the application starts, without any error. After you close it again, you'll find that "echo" still prints the expected line
10.0.0.126:0
so we know $DISPLAY contains what we said it should and didn't magically return to :0.0

I don't have the applications installed you tried, but I used xchat, the calculator etc., and they all never throw an error. they just start up as if nothing had happened - as if they wouldn't read $DISPLAY at all.

OK, testing as you said above:

xterm launches, echoes DISPLAY
browser (opera) launches, echoes the DISPLAY I set
fmradio - doesn't launch, w/GTK+ can't open display <IPADDR>
vncviewer - doesn't launch, no GTK error, echoes DISPLAY
gpe-calendar - doesn't launch w/GTK+ can't open display <IPADDR>
pwsafe - doesn't launch w/GTK+ can't open display <IPADDR>

So, some apps do honor $DISPLAY and some don't? Am I interpreting that right? But, even if they honor it, they won't export over SSH.

This is getting too technical for me now; I always thought that this X feature is handled be the X framework itself and not by each single application.

Maybe Xomap simply doesn't support this feature at all? I tried to search google for further information about Xomap and remote X displays, but didn't find anything useful except:

on the mailing list here. (The thread is about the reverse situation, forwarding from the desktop to the 770, but nonetheless it's about X and TCP-connections.)

Maybe one of the developers could tell us more.

Thanks for the thread pointer. I'll put this on the back burner for now I guess!

I just installed winaxep (http://www.labf.com/winaxeplus/index.html) on a MS Windows XP machine, then used their "telnet_ssh" to ssh to my N800 (with openssh installed). After "export DISPLAY=192.168.xxx.yyy:0" (the windows machine's IP address) and then "leafpad", the leafpad main window opened up on the XP desktop! Same for mirage (picture viewer from garage) and claws-mail. I was really surprised after all those failed trials to forward X-apps from the n800 to my linux desktop!! However, there where no window borders and menus were accessible via alt-f4 only. Nevertheless it's a starting point...