Subject: com driver problems
To: None <current-users@NetBSD.ORG>
From: Geir Inge Jensen <>
List: current-users
Date: 11/18/1996 14:41:56

I sup'ed current a week ago, and compiled it successfully. My last
current-kernel was from April. It installed fine, but I encountered a
little problem with the kernel. It boots, but as soon as it hits 'ttyflags'
in /etc/rc, it locks up.

After some digging in the kernel, I found that it loops in com.c, procedure
comopen, with the following statement:

/* flush any pending I/O */
while (ISSET(bus_space_read_1(iot, ioh, com_lsr), LSR_RXRDY))
        (void) bus_space_read_1(iot, ioh, com_data);

Somehow, it seems that there always are pending incoming packets (although
there is nothing connected to the port!). Do I have broken hardware?

I tried to comment out that code segment, and NetBSD boots fine. However,
none of the com-ports works as expected. When I boots my 1.1B (April)
kernel, everything works fine.

Unfortunately, I don't have the old sys/dev/isa/com.c and
sys/arch/i386/include/bus.h, so I can't see what has changed. Any ideas of
what I can do?

As you can see, it is an i386 (if it matters).

Geir Inge Jensen                               Department of Computer Science
                                               University of Tromsų, Norway
URL  :            Phone: +47 77 64 42 37