>In message <9506071350.AA09758@cthulhu>  Mike Long wrote:
>> Something in the last com driver fix disagrees with my modem (DSI
>> Connection 96+).  Any process that tries to use it hangs; ps(1)
>> reports that it is blocked in 'tty in' or 'tty out'.

I've experienced similar com driver hangs infrequently during kermit
sessions and always when I try to use either SLIP or PPP (pings and
low-traffic telnet are ok; ftp and X always hang the driver).

>There is bug in some chipsests where TX interrupts can get lost.
>Check my chnages in com.c (for 1.0) in my pcmcia-stuff.
>ftp.uni-mainz.de://pub/NetBSD/misc_features/Stefan/
>Basicly before going to sleep on tty out check if the chip is 
>realy busy sending some stuff, and also after you handled all interrupts
>and the driver is expecting a TX interrupt if the chip is still
>busy sending.
>If the chip it is not busy 'fake' a TX-interupt.
>This problem only happend with non FIFO chips, looks like
>enabling the send-FIFO's triggers it for FIFO chips too.

Thanks for the info!  I had figured it had something to do with my "all-in-one"
chip IO card and had given up on SLIP/PPP until I could afford new 16550A-based
serials.  Now perhaps I won't have to wait.  :-)

Is there a mailing list I could join to hear more about these obscure driver
fixes?  This is the first time the problem has been acknowledged on the
i386 mailing list, though it probably effects many NetBSD/i386 users.

Max