contrib/FAQ/FAQ-06

6.0 Kernel Configuration

6.0.1:  When I compile a kernel with multi-port serial code, it tells me
        that only the first port is probed and the rest skiped due to
        interupt conflicts.  How do I fix this?

The problem here is that FreeBSD has code built-in to keep the kernel from
getting trashed due to hardware or software conflicts.  The way to fix this
is to leave out the irq settings on other ports besides the first.  Here is
a example:

#
# Multiport high-speed serial line - 16550 UARTS
#
device    sio2    at isa? port 0x2a0 tty irq 5 flags 0x501 vector siointr
device    sio3    at isa? port 0x2a8 tty flags 0x501 vector siointr
device    sio4    at isa? port 0x2b0 tty flags 0x501 vector siointr
device    sio5    at isa? port 0x2b8 tty flags 0x501 vector siointr

You may also want to look at the multi-port serial FAQ in
/usr/src/contrib/FAQ/OTHER-FAQS/multi-port.serial.FAQ.


6.0.2:  FreeBSD is supposed to come with support for QIC-40/80 drives but
        when I look, I can't find it.

You need to uncomment the following line in the generic config file (or add
it to your config file) and recompile.

controller      fdc0    at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr
disk            fd0     at fdc0 drive 0
disk            fd1     at fdc0 drive 1
#tape           ft0     at fdc0 drive 2
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


6.0.3:  Does FreeBSD support SYSV IPC, shared memory, etc?

Yes, FreeBSD supports SYSV IPC.  This includes shared memory, messages and
semaphores.  You need to add the following lines to your kernel config to
enable them.

options         SYSVSHM
options         "SHMMAXPGS=64"          # 256Kb of sharable memory
options         SYSVSEM                 # enable for semaphores
options         SYSVMSG                 # enable for messaging

Recompile and install.