Serial console problems with stable/8

[Stefan Bethke]

Am 12.09.2010 um 17:26 schrieb Oliver Fromme:

> I cannot even su(1) to root because it tries to print
> a message to the console, so it hangs, too.  For the same
> reason I can't use shutdown(8) either.  :-(
> 
> This is what a hanging su(1) command looks like in ps -alxww:
>  UID   PID  PPID CPU PRI NI   VSZ   RSS MWCHAN STAT  TT       TIME COMMAND
>    0  1533  1532   0  76  0  3392  3180 ttydcd I+     0    0:00.05 su (zsh)
> 
> Interestingly, the KDB sequences CR ~ ^B/^P/^R/ do work,
> which use the "low-level" console.  So only the "high-level"
> console is frozen.

Looking at the WCHAN, I'd speculate that it's waiting for DCD to become active. Are you using a proper cable with handshaking, or a three-wire cable?

See what stty thinks the port is set to.  It probably has clocal set, but shouldn't. See if you can unwedge it by setting -clocal with stty, then pick a proper cable or gettytab entry.


Stefan

-- 
Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811