This weekend I looked into why my Hayes ESP serial board hangs my system. It
appears that when comioctl gets called to set the baud rate on the board, this
generates and endless loop of interrupt calls to comintr. I compared this to
the behavior of a 16450 port. It generates an interrupt also after the call to
comioctl, but only one. I was looking into this by running tip, but the same
symptoms appear when I run slattach. In slattach, the system hangs during a
call to tcsetattr(fd, TCSADRAIN, &tty). I don't have a technical manual on the
Hayes ESP board, so I don't know how much further I can take this. Any ideas?

BTW, I did add the DMA flag to FIFO_ENABLE in com.c and rebuilt the kernal. I
also exchanged the board with a new one, to eliminate a board problem
possibility. To those of you who has the ESP board working in your systems.
Did you have to modify anything else in your system to make it work?

Gerry Simmons
simmons@darykon.wa.com