[CentOS] How do I configure additional serial ports?

Fri Mar 9 19:30:30 UTC 2007
Alfred von Campe <alfred at 110.net>

On Mar 9, 2007, at 12:21, John R Pierce wrote:

> this also explains why I could never get more than a couple ports  
> working on a 8 port card I picked up to use as a unix server serial  
> console controller.

Yup, and it also explains all the behavior I've seen.

> and, yeah, if I can request CentOS Plus kernel consider supporting  
> more serial ports, chalk me in!

Me too.  I just checked, and it appears that the CentOS Plus kernel  
does not have the additional ports configured by default.  So I bit  
the bullet and started to build my own kernel.  I had the kernel- 
devel package installed for my current kernel.  I did a "make  
xconfig" in /usr/src/kernels/2.6.9-42.0.10.EL-i686 (after doing a  
"yum install qt-devel") and changed two options under Device Drivers - 
 > Character devices -> Serial drivers:

   1. Changed "Maximum number of non-legacy 8259/16559 serial ports"  
from 4 to 12
   2. Enabled "Support more than 4 legacy serial ports" under "Extend  
8250/16550 serial driver options"

I saved the config, but when I do a make, I get the following error:

# make
   CHK     include/linux/version.h
   SPLIT   include/linux/autoconf.h -> include/config/*
   CHK     include/asm-i386/asm_offsets.h
   HOSTCC  scripts/genksyms/genksyms.o
   HOSTCC  scripts/genksyms/lex.o
   HOSTCC  scripts/genksyms/parse.o
   HOSTLD  scripts/genksyms/genksyms
   CC      scripts/mod/empty.o
   HOSTCC  scripts/mod/mk_elfconfig
   MKELF   scripts/mod/elfconfig.h
   HOSTCC  scripts/mod/file2alias.o
   HOSTCC  scripts/mod/modpost.o
   HOSTCC  scripts/mod/sumversion.o
   HOSTLD  scripts/mod/modpost
   HOSTCC  scripts/kallsyms
   HOSTCC  scripts/pnmtologo
   HOSTCC  scripts/conmakehash
make[1]: *** No rule to make target `init/main.o', needed by `init/ 
built-in.o'.  Stop.

I even tried to re-install the kernel-devel RPM to no avail.   
Granted, I've never had to rebuild a CentOS kernel before, so maybe  
I'm missing some steps.  But I thought all you needed to do was "make  
xconfig" (or "make menuconfig") followed by a make.