Subject: kern/4683: 16550 uart driver can freeze machine
To: None <gnats-bugs@gnats.netbsd.org>
From: Frank J. Beckmann <frank@damogran.agala.harz.de>
List: netbsd-bugs
Date: 12/13/1997 20:59:46
>Number:         4683
>Category:       kern
>Synopsis:       uucico triggers bug in 16550 uart driver
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Dec 13 15:05:01 1997
>Last-Modified:
>Originator:     Frank J. Beckmann
>Organization:
	agala naga doron
>Release:        NetBSD 1.3_BETA <NetBSD-current source date>
>Environment:
	
System: NetBSD damogran.agala.harz.de 1.3_BETA NetBSD 1.3_BETA (DAMOGRAN) #1: Sat Dec 13 11:32:28 CET 1997 frank@damogran.agala.harz.de:/usr/src/sys/arch/amiga/compile/DAMOGRAN amiga


>Description:
	
Uucico aborts due too much errors or the machine freezes when a serial
line with a 16550 uart ist used. The problem is not the uucico. It
works with serial lines which  use a Motorola 68xxx. The uucico of
NetBSD 1.2.1 does not work with the 16550 driver of netBSD 1.3 either.
Ppp works fine with the 16550 driver. Uucp over ppp works too.
Using a 7bit protocol (f) does not help. Using a streaming protocol,
like f protokol, freezes the machine. The last entries in 
/var/log/messages say:
"call_sicallback: 76 more dynamic structures 398 total"
The machine freezes when total is about 66000 which happens very fast.
This happens when uucico receives data, sending is ok.
mgetty coplains "tcsetattr failed: Invalid argument", but I don't know
if that is the saame problem. Mgetty does not complain when the
16550 driver is not used.

I just did another test, rz (zmodem) does not work with the 16550 driver i
either. Sending data with sz is no problem.

See also pr #4596. I think that is the same problem.

>How-To-Repeat:
	
Just try to use uucico with the 16550 driver (Intel PC or Amiga with
HyperCom 4).

>Fix:
	
unknown
>Audit-Trail:
>Unformatted: