Re: Magic SysRq +

Vojtech Pavlik
2001-09-21T09:12:50Z

On Fri, Sep 21, 2001 at 11:07:01AM +0200, David Balazic wrote:
> Vojtech Pavlik (vojtech@suse.cz) wrote :
>
> > On Wed, Sep 19, 2001 at 08:56:13AM -0700, Randy.Dunlap wrote:
> > > (and maybe earlier...)
> > >
> > > Simple problems grow...
> > >
> > > Keith Owens has already noted one problem in sysrq.c (2.4.10-pre12).
> > >
> > > Beginning:
> > >
> > > I have an IBM model KB-9910 keyboard. When I use
> > > Alt+SysRQ+number (number: 0...9) on it to change the
> > > console loglevel, only keys 5 and 6 have the desired
> > > effect. I used showkey -s to view the scancodes from
> > > the other <number> keys, but showkey didn't display
> > > anything for them. Any other suggestions?
> >
> > Most likely the keyboard scanning matrix doesn't allow that combination.
> > Quite a large number of keyboards doesn't allow multiple keys pressed
> > (except for shift, ctrl, alt, which are separate) at once.
>
> "we saved 13 cents on keyboard costs !"

Oh yes, you can save some diodes if you don't want all keys pressed at
once ...

> On my Cherry G-83 keyboard ( crap/shit/$"#$"$" !!! ) the alt-SysRq-B
> ( reboot ) combination does not work. I don't know about other combinations.
>
> Workaround that works for me : press ALT , press SysRq , release ALT , press B

Yes, that's why this workaround was implemented.

--
Vojtech Pavlik
SuSE Labs