Subject: kern/12547: console break signal ignored
To: None <email@example.com>
From: None <firstname.lastname@example.org>
Date: 04/04/2001 10:32:31
>Synopsis: console break signal ignored if DDB not defined
>Arrival-Date: Wed Apr 04 08:37:00 PDT 2001
>Originator: Ron Roskens
>Release: NetBSD-current 20010401
System: NetBSD reality.roskens.com 1.5T NetBSD 1.5T (WEBHEAD.MP) #6: Tue Apr 3 14:02:15 CDT 2001 email@example.com:/coda/src/sys/arch/sparc/compile/WEBHEAD.MP sparc
When the cnmagic functionality was added to the kernel, it re-wrote the way
that a kernel could be dropped into the kernel debugger or prom mode.
cn_trap() is called to send you to the debugger, but on systems which don't
define DDB this results in console_debugger() being defined as a NOP
do/while loop. Systems which have a prom mode now cannot reach that mode.
On a sparc ss10, configure a kernel without DDB support. Boot via the resulting
kernel, and send it break signal on the console. Watch it display ^@ instead
of dropping you to the prom mode.