What type of system is this on?  I had the exact same problem on my
digital Ultra HiNote II laptop, but I have never seen it on any other
system.  Unfortunately I had to give the laptop back to my old employer
before I could track down the real problem.

Dave

> I have been tracking current for some years now, and it has always worked
> reasonably well. Last november I sup'ed current and it compiled fine.
> However, I got into a kernel loop as soon as I entered 'ttyflags' in
> rc. This was due to a problem in com.c and I was forced to go back to
> a clean 1.2 system.
> 
> Yesterday I got an internal error in /usr/bin/ld, and I thougt it was time
> to upgrade my system again. I did report my problem last time, and I
> assumed it would be fixed by now. However, the kernel loops at the very
> same place. It might be a HW-related bug, but it works fine with a clean
> 1.2 system (and every release before that).
> 
> This is the statement that loops in procedure com_iflush:
> 
> /* 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!). How can I check that the
> bus_space_read_1 actually reads the data? Could it be that either iot or ioh
> has wrong values? Is the port initialized correctly?
> 
> Output from boot messages:
> 
> ...
> May 19 23:11:27 jk1 /netbsd: com0 at isa0 port 0x3f8-0x3ff irq 4: ns8250 or ns16
> 450, no fifo
> May 19 23:11:27 jk1 /netbsd: com1 at isa0 port 0x2f8-0x2ff irq 3: ns8250 or ns16
> 450, no fifo
> May 19 23:11:27 jk1 /netbsd: com2 at isa0 port 0x3e8-0x3ef irq 5: ns16550a, work
> ing fifo
> May 19 23:11:27 jk1 /netbsd: com3 at isa0 port 0x2e8-0x2ef irq 3: ns8250 or ns16
> 450, no fifo
> ...
> Setting tty flags
> com0: comparam -clocal +dcd +ts_carr_on -dtr -tx_stopped
> com0: comparam -crtscts +cts -ts_ttstop -rts -rx_blocked
> com0: comiflush -clocal +dcd +ts_carr_on +dtr -tx_stopped
> com0: comiflush -crtscts +cts -ts_ttstop +rts -rx_blocked
> 
> 'comiflush' has I put in just before the statement that loops. Anybody
> that knows how to fix this? Any clue at all to how I can debug this?
> It would be nice to track current again (and still be able to use the
> com ports ;)
> 
> Keep up the good work.
> 
> -Geir Inge