Re: System hangs while rebooting.

[Stephen Powell <zlinuxman@wowway.com>]

On Fri, 26 Mar 2010 07:32:31 -0400 (EDT), Usman Ajmal wrote:
> 
> I have Debian installed on two computers. On one of them it reboots quite
> finely but I am having following problem with rebooting Debian on my second
> computer.
> 
> When i type reboot at the linux prompt, following messages appear and system
> hangs up after saying "Restarting System":
>
> 
> *Broadcast message from root@myname (tty1) (Sun Jan 17 11:23:26 2010)
> 
> The system is going down for reboot NOW!
> INIT: Switching to runlevel: 6
> INIT: Sending processes the TERM signal
> Saving system clock
> Stopping enhanced syslog: rsyslogd.
> Asking all remaining processes to terminate...done.
> Deconfiguring network interfaces...done.
> Cleaning up ifupdown....
> Deactivating swap...done.
> [ 31.789103] Restarting System.
> _
> *
> Normally when the sytem is busy "_" sign blinks but "_" at the last line
> above does not blink which shows, the system hanged up. I tried all keys but
> the screen is still frozen at the same point.
> 
> The difference that I noted between my two computers is that I don't have
> ACPI support in the BIOS of the system which is giving me this error whereas
> the BIOS of my first computer do have ACPI support on which Debain do not
> give this Restart hanging problem.
> 
> I have also disabled running the acpid script by running "update-rc.d -f
> acpid remove" but the problem still persists on the second computer.
> 
> Any ideas to solve or get around this problem?
> 
> Thanks a lot.

OK, there are several items here.  First of all, the preferred way to
reboot is to issue

   shutdown -r now;exit

from a virtual console as root or, even better, logout of all sessions
and then use the

   Ctrl+Alt+Delete

key combination on a virtual console (not the X console).  Some Desktop
Environments (such as GNOME) also provide a way to shutdown the system
from their system menus.  "reboot" should not be issued from the command
line.  "reboot" is issued as the final command in the final script
(/etc/rc6.d/S90reboot) run during a clean system shutdown by one of the
above methods.

Second, assuming you are running a stock Debian kernel, ACPI is compiled
into the kernel and runs whether you want it to or not.  However, if
you boot with the kernel boot parameter "acpi=off" you can disable ACPI.

Third, maybe your BIOS doesn't support ACPI, but maybe it supports APM?
If so, you can get some power management function that way.  For example,
if you create a file called /etc/modprobe.d/local with the contents

   options apm power_off=1

and then list apm in /etc/modules, you can get "shutdown -h now" to
power-off the machine.  Finally, check /etc/inittab to make sure that
Ctrl+Alt+Delete is defined properly there.  It should say something
like:

   # What to do when CTRL-ALT_DEL is pressed.
   ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

Note: be *very* careful when editing this file.  A syntax error in this
file may leave you with a system that will not boot.  If you have to
change anything in /etc/modprobe.d or if you have to change
/etc/inittab, you should rebuild your initial RAM filesystem with
update-initramfs and re-run lilo (if lilo is your boot loader).
The changes will take effect upon reboot, and therefore the
*second* reboot after making these changes will show an altered
shutdown behavior.

HTH

-- 
  .''`.     Stephen Powell    <zlinuxman@wowway.com>
 : :'  :
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