serial console issues (2.6.x)

[Adam Snodgrass <wolf@fyrestorm.com>]

Hi,

I've got two odd issues I've encountered that I cannot solve.  Both are
seen on two different machines (U30, E250), 2.6 kernel (tried: 2.6.12.1,
2.6.12.3, both vanilla sources).  Both issues relate to serial console
(neither machine has any video).

The first issue is that the kernel seems to feel it necessary to print
70+ lines of whitespace (in groups of two 30 or 40ish packs, with an
actual "reset-cursor-to-0,0" after each) when booting.  It's making
troubleshooting some problems I'm having maddeningly difficult.

The activity seems to take place just prior to "PROMLIB: ..." output,
and nicely destroys my scrollback buffer.  I first suspected the use of
initrd, but a non-initrd kernel has the same behavior, so it seems to be
in the kernel itself.  This behavior occurs regardless of the terminal I
use (minicom, cisco 2509).

The second issue arrises if the kernel panics during boot (like a stupid
system operator forgot to set the root= line correctly in silo.conf ><);
the serial console becomes totally unusable.  On an ix86 box, I wouldn't
care; but on a sparc machine, I want to be able to send a break and use
the OBP to recover.  This issue, however, means I have to go physically
power cycle the box.

This happens whether I use a direct serial link with minicom, or my
"reverse telnet" via a 2509.  The 2509 reports "noCTS noDSR*  DTR RTS"
after this event (normal operation is "CTS DSR* DTR RTS").  It seems to
cause any input I provide after the panic to be queued on my end, since
as soon as the machine is back up it drops to OBP if I sent a break
signal after the panic.

Both issues are highly irritating, the latter especially so when I'm not
at the machine's physical location.  Any ideas?

Thanks,

-- 
Adam
wolf@fyrestorm.com