ssh -Y -l user etc,etc

[gene heskett]

On Friday, February 25, 2011 03:05:56 pm Eirik Byrkjeflot Anonsen did 
opine:

> gene heskett <gheskett at wdtv.com> writes:
> > On Thursday, February 24, 2011 10:23:08 pm Glynn Clements did opine:
> >> gene heskett wrote:
> >> > So that probably explains where the 10.0 is coming from, but not
> >> > where I might change it?  That seems to be the $64k question...
> >> 
> >> Why do you need to change it?
> > 
> > Because its not working? :)
> 
> I think we're getting to the root of the problem here :)
> 
> So, you want to run emc on the machine called 'shop', and you want it to
> display its UI on the machine called 'coyote'.
> 
> Using 'ssh -Y shop' (on coyote) will make ssh create a proxy X server on
> 'localhost:10.0' on 'shop' (by default).  This X server will only
> forward all requests to the real X server on 'coyote'.  That's why you
> would want the DISPLAY variable to say 'localhost:10.0'.
> 
> In principle, you could set DISPLAY to 'shop:10.0' and connect to the
> same X server (the proxy created by ssh), but that requires setting
> X11UseLocalhost to no.  And it probably won't help, unless emc is doing
> something very strange when it tries to connect to X.
> 
> To connect directly to the real X server, you'd have to set DISPLAY to
> 'coyote:0.0' (assuming the X server on coyote is using the default
> setting).  However, that will only work if:
> 
> 1. The X server on coyote is set up to listen to tcp.
> 2. You have set up the proper credentials to allow connections to it.
> 
> For 1, most current systems turn off tcp support when starting X as it
> is not particularly useful (for most people) and an obvious security
> issue.  I assume this is still done by passing the '-nolisten' option on
> startup of the X server.
> 
That is in effect here on "coyote", I can see it on the htop display.

> For 2, you have to wrestle with xauth or xhost to get things set up
> correctly.
> 
> However, I suspect this isn't really what you want anyway.  None of this
> should be necessary.  'ssh -Y' should be plenty of good enough.
> 
> 
> It is probably best to split up debugging into two stages: first make
> sure the X setup works, and then figure out why emc fails to use it.  If
> a "simple" X application (e.g. xterm) can successfully start up on
> 'shop' and display its window on 'coyote', then the X setup is working
> and you shouldn't need to fiddle with DISPLAY or X11UseLocalhost.
> 
> If xterm works correctly, then it is most likely emc that has a bug of
> some sort.  It could be useful to try setting X11UseLocalhost to no,
> just to check that it doesn't make a difference.  (If that actually
> makes emc work, it is probably about time to make a bug report to
> emc...)
> 
Maybe so Eirik, I just changed the debug level from 0 to 1, which should 
give a better idea of what its choking on, then issued an "emc -l" which 
tells it to load the last active config, and got this:

gene at shop:~/emc2/configs/genes-mill$ emc -l
EMC2 - 2.4.6
Machine configuration directory is '/home/gene/emc2/configs/genes-mill'
Machine configuration file is 'genes-mill.ini'
EMC2 is still running.  Restart it? [Y/n] Y
Cleaning up old EMC2...
Shutting down and cleaning up EMC2...
Waiting for other session to finish exiting...lockfile still not removed
Cleanup done
Starting EMC2...
insmod: error inserting '/usr/realtime-2.6.32-122-
rtai/modules/emc2/rtapi.ko': -1 Unknown symbol in module
Realtime system did not load
Shutting down and cleaning up EMC2...
RTAPI: ERROR: could not open shared memory (errno=2)
HAL: ERROR: rtapi init failed
halcmd: hal_init() failed: -22

However, that did not recur on the next attempt, it went back to this:

gene at shop:~/emc2/configs/genes-mill$ emc -l
EMC2 - 2.4.6
Machine configuration directory is '/home/gene/emc2/configs/genes-mill'
Machine configuration file is 'genes-mill.ini'
Starting EMC2...
Traceback (most recent call last):
  File "/usr/bin/axis", line 3844, in <module>
    o = MyOpengl(widgets.preview_frame, width=400, height=300, double=1, 
depth=1)
  File "/usr/bin/axis", line 354, in __init__
    Opengl.__init__(self, *args, **kw)
  File "debian/tmp/usr/lib/python2.6/dist-packages/rs274/OpenGLTk.py", line 
219, in __init__
  File "debian/tmp/usr/lib/python2.6/dist-packages/rs274/OpenGLTk.py", line 
167, in __init__
  File "debian/tmp/usr/lib/python2.6/dist-packages/rs274/OpenGLTk.py", line 
93, in __init__
  File "/usr/lib/python2.6/lib-tk/Tkinter.py", line 1935, in __init__
    (widgetName, self._w) + extra + self._options(cnf))
_tkinter.TclError: Togl: couldn't get visual
Shutting down and cleaning up EMC2...
Cleanup done
EMC terminated with an error.  You can find more information in the log:
    /home/gene/emc_debug.txt
and
    /home/gene/emc_print.txt
as well as in the output of the shell command 'dmesg' and in the terminal

It appears to me that the present 'axis' gui isn't capable of using an X 
proxy anymore.  a dmesg is also rather verbose.

Interesting.  We may be onto the scent trail now.  I'll hit the emc mailing 
list with this, many thanks for the hand holding Eirik, I appreciate it.

I may be back if they claim it works for everyone else.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
<http://tinyurl.com/ddg5bz>
It looks like it's up to me to save our skins.  Get into that garbage 
chute,
flyboy!
		-- Princess Leia Organa