switch users --> black screen, no response [in 12.04]

[chris]

On Sat, 2013-05-18 at 14:38 +0100, pete smout wrote:
> On 18/05/13 10:01, chris wrote:
> > On Fri, 2013-05-17 at 22:21 -0700, rikona wrote:
> >> Hello chris,
> >>
> >> Friday, May 17, 2013, 2:06:10 PM, chris wrote:
> >
> >>
> >>> Try from the keyboard
> >>> holding ctr alt syrq  the press in sequence rseiub
> >>> This is the sysreq command for a clean shut down and reboot which should
> >>> safely close the usb drives.
> >>
> >> WOW - that is a keeper! I didn't know about sysreq, but now see how
> >> useful it can be.
> >>
> >>> has saved my bacon on more than one occasion
> >>
> >> I can believe that! Thanks much - that is a really useful piece of
> >> info...
> >>
> >> --
> >>
> >>   rikona
> >>
> >>
> > There are other sysreq commands, and I can suggest you can google for
> > them
> > Cheers Chris
> >
> >
> >
> Hi,
> 
> Apparently they have to be enabled!! see 
> http://www.unixmen.com/use-magic-sysrq-combination-key-to-recover-from-a-frozen-system-in-linux-ubuntu/
> 
> good idea though seems to me that it should be enabled as default!
> 
> Pete
> 
> 

Has been enabled by default in every Ubuntu version I have used.
ie no need to enable it it is part od the kernel code