Incomplete shutdown on some LTSP clients (shutdown hangs/freezes)

[John Hupp]

On my Lubuntu and Edubuntu 12.04 LTSP test networks, I find that some 
clients do not shut down completely.

On the Lubuntu network, one eMachine client stops at a black-and-white 
text screen that says:
     Ubuntu 12.04
     .... * Asking all remaining processes to terminate ...
     [255.161402] SysRq : Power off
     [255.173722] Power down.
       [OK]
     [255.280060[ SysRq : Power Off
     [255.280220] Power down.
     * All processes ended within 1 seconds ....    [OK]
A simple press of the power button does not turn off the machine at that 
point.  I have to press and hold it 5 seconds or so.

Also on the Lubuntu network, an HP stops at the same screen, but a 
simple press of the power button turns it off.

A Dell on the Lubuntu networks shuts off cleanly and completely within a 
few seconds.

---------------------

On the Edubuntu network, all clients have to invoke Shutdown from the 
desktop and from the login screen.  After choosing Shutdown from the 
desktop (and then presenting a dialog for Shutdown or Restart), it drops 
back to the login screen, and there one chooses Preferences: Shutdown.  
[Very tedious, but that's not my real interest in this post.  And as a 
footnote, the server shuts down cleanly after the two clicks on the desktop.

But regarding specific client machine behavior on the Edubuntu network, 
the above eMachine hangs at a black screen after Preferences: Shutdown 
from the login screen.  I forgot to make a note of whether a simple 
press of the power button shuts it off from here, or whether a 
press-and-hold was required as it was on the Lubuntu net.

The above HP hangs at a white screen after Preferences: Shutdown from 
the login screen.  A simple press of the power button shuts it off from 
here.

The above Dell shuts down cleanly after Preferences: Shutdown from the 
login screen.

---------------------

One other behavior that was of interest to me but that I did not 
thoroughly document was that even on machines where Shutdown hangs, it 
seems generally to be the case that Restart does not hang.  The machine 
proceeds smoothly to POST and reboot.

---------------------

So I am wondering if I can get all the clients to shut down cleanly via 
the interface Shutdown commands.

If not, is there a script that will produce a clean shutdown?

Or failing that, can I insert a splash screen at the end of the shutdown 
process something like Windows 95/98 used on machines where it could not 
execute a complete shutdown automatically? (The screen said something 
like "It is now safe to turn off your computer.")

Speaking of Windows 95/98's shutdown process, I recall that the issue 
had to do with power management drivers not fully supporting the 
hardware on some motherboards, or not finding the hardware that power 
management did fully support.  But beyond that, it was possible to 
not-install/uninstall/disable power management on machines that did 
support full shutdown, then install/reinstall/re-enable power management 
but not recover the ability to do a full shutdown.  So it wasn't always 
just a question of supported hardware.

Also regarding Win 9x, that splash screen may have been an integrated 
part of all shutdowns.  I recall seeing it flash on-screen for a split 
second even on machines that were on their way to a full automatic shutdown.



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