hard lock-up writing to tape

Bruce Evans bde at zeta.org.au
Tue Nov 18 19:30:16 PST 2003

On Tue, 18 Nov 2003, Mike Durian wrote:

> On Monday 17 November 2003 04:41 pm, Mike Durian wrote:
> >
> > I was finally able to get some partial success by setting flag 0x30
> > for sio1.  When I'd boot, I'd get console messages on my remote
> > tip session.  However, I'd only receive those messages printed
> > from user-level applications.  I would not see any of the bold-face
> > messages from the kernel.
> I'm still stumbling with the remote serial console.  Can someone
> who does this often test and verify they can use COM2 as the
> serial console - and then tell me what you did.

Moving the 0x10 flag from sio0 to sio1 should be sufficient for the kernel
part.  Setting the 0x20 flag for sio1 together with the 0x10 flag should
mainly save having to edit the flag for sio0.  If the kernel's serial
console is the same as the boot blocks', then it should use the same speed
as the boot blocks set it too.  Otherwise there may be a speed mismatch.

> The best I can manage is described above and then I get neither
> the bold kernel messages nor the debugger prompt.

This could be from a speed mismatch or from kern.consmute somehwo getting

Some of this stuff can be configured after booting:
- RELENG4 has non-broken boot-time configuration which allows changing
  during the boot.
- -current has the kern.console sysctl for enabling multiple consoles
  (buut only 1 sio one).  You can boot with a syscons console and then
  enable the serial, and the latter should work if it is on a working
  port to begin with.  Anyway, this sysctl shows which sio port can be
  a console, if any.
- RELENG_4 and -current have the machdep.conspeed sysctl for setting the
  console speed.


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