SYSRQ...(part2)

[Mike A. Harris]

On Mon, 24 Jan 2000, willy tarreau wrote:

>The problem is due to the fact that keyboards internal
>controllers see keys as intersection of columns and rows. It's
>not uncommon that multiple rows and cols connexion collide so
>that the controller can't understand what's happening. In your
>case, I think you receive the 0xd4 code (SysRQ release) at the
>moment you press the P key, just before it sends 0x19. Your
>keyboard simply considers it can't see the SysRQ key anymore
>when Alt and P are pressed together.

No, I've finally isolated the problem.  My SYSRQ key generates
the make and break codes one after the other without waiting for
the release.  In other words, when I press SYSRQ, it sends:

0x54 0xd4

It does NOT wait for me to release the key, therefore there is no
way I can press another key in the middle.  The kernel sees a
press of SYSRQ as a press and release, even if it is held down,
therefore SYSRQ is not possible.

>So the solutions are : 
>  - either change your keyboard

This is how I discovered the truth of my problem.  ;o)

>  - or replace SysRQ with another key. Common passive
>    keys work well (alt, ctrl, shift ...). Why not
>    something like Lalt+RCtrl (or even more if you
>    agree to modify the sources).
>
>Netware, for example, uses Alt-Lshift-Rshift-Escape to
>enter its debugger. I don't know about any keyboard
>on which Alt+[LR]Shift don't work together.

Yes, I am going to have to modify the code which activates SYSRQ.
It cannot just be a simple key replacement however because SYSRQ
key is the only key with a unique code when ALT is held down...

So, I need some obscure impossible to do accidentally combo like
you described above.  I just need to determine how to do it in
the kernel source without screwing my kernel up.  ;o)

Thanks for your help!
TTYL

--
Mike A. Harris                                     Linux advocate     
Computer Consultant                                  GNU advocate  
Capslock Consulting                          Open Source advocate

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