In Linux, only the kernel can directly act upon a piece of hardware. Therefor we need to add the Comedi module to the kernel. There are a few different steps.

1. Add some info so monitoring programs recoginze your card.
2. Making sure that the Linux Kernal source is right. Since the Comedi module will be complied against the kernal source it is important that the source is complete. When Linux is installed pre-complied (as is normal) the source may not be complete.
3. Compile the Comedi Module. We are using version comedi-0.7.66
4. Install comedilib
5. Starting up the Comedi Module.

A conveient utility for seeing what is on you pci bus is /sbin/lspci[man lspci]. If I have just put in a new card there is a good chance it will not be recognived (see "Unknown device 2a70" below):

[he3]$ /sbin/lspci 00:00.0 Host bridge: Intel Corp. 440FX - 82441FX PMC [Natoma] (rev 02) 00:07.0 ISA bridge: Intel Corp. 82371SB PIIX3 ISA [Natoma/Triton II] (rev 01) 00:07.1 IDE interface: Intel Corp. 82371SB PIIX3 IDE [Natoma/Triton II] 00:0b.0 VGA compatible controller: Matrox Graphics, Inc. MGA 2064W [Millennium] (rev 01) 00:0f.0 Class ff00: National Instruments: Unknown device 2a70 00:11.0 Ethernet controller: 3Com Corporation 3c900 Combo [Boomerang]

I need to update the file /usr/share/hwdata/pci.ids [download].
Now:

[he3]$ /sbin/lspci 00:00.0 Host bridge: Intel Corp. 440FX - 82441FX PMC [Natoma] (rev 02) 00:07.0 ISA bridge: Intel Corp. 82371SB PIIX3 ISA [Natoma/Triton II] (rev 01) 00:07.1 IDE interface: Intel Corp. 82371SB PIIX3 IDE [Natoma/Triton II] 00:0b.0 VGA compatible controller: Matrox Graphics, Inc. MGA 2064W [Millennium] (rev 01) 00:0f.0 Class ff00: National Instruments PCI-6024E 00:11.0 Ethernet controller: 3Com Corporation 3c900 Combo [Boomerang]

This just means that it knows the name of the card - but still nothing about using it.

Since the Comedi module will be complied against the kernal source it is important that the source is complete. When Linux is installed pre-complied (as is normal) the source may not be complete.

So at this stage you will go through the early stages of compiling the kernel - without actually compiling and installing a new kernel (yes - you could do that if you wanted to - but you do not need to).

You need to go through the configure and make dependences steps.

The following instructions are for location /usr/src/linux-2.4.18-27.7.x (or what ever version of Linux you have). If you perform these in that area you need to be root. You can do this in user-space and not as root, but you will need to be root later anyhow to install comedi.

• Move to the Linux source tree directory. Normally:
  cd /usr/src/linux-2.4.18-27.7.x
  • if you have several version of the Linux kernel source, make sure you are using the one you are running.
  • you can figure out what that is with the command:
    uname -r
• Look in the Makefile. On about the fourth line it may say:

  EXTRAVERSION = -27.7.xcustom

  if it has the word "custom", edit it so it says:

  EXTRAVERSION = -27.7.x

  The RedHat release of Linux includes the word "custom" such that if you custom build a kernel it will not over write the original. We are not going to build a new kernel.

• make clean to clean up the area
• make mrproper to make the area very clean
• make oldconfig There are four ways of configuring the kernel. This is where you get to decide what is compiled into the kernel. Note: comedi is NOTE compiled into the kernel - it is loaded later! Still - an explination of the methods of makeing the configuration.
  1. make config Ask you a number of questions.
  2. make menuconfig Text based color menus, radiolists & dialogs.
  3. make xconfig X windows/GUI based configuration tool.
  4. make oldconfig Answer all questions based on last time a config was done. These answers are located in ./.config . If that file is not there it goes to: configs/kernel-2.4.18-i686.config
• make dep This makes a list of the dependencies and puts them in the file tmp_include_depends . That is the file that comedi needs to be compiled correctly. That is the whole point of this step with the Linux source.

Next we compile the comedi module. By defalt it will drive four cards. We includ the instructions to add more cards.

• Copy the tar-file comedi-0.7.66.tgz to you working directory (ie. /scratch works well).
• tar -zxvf comedi-0.7.66.tgz to uncompress and unpack it.
• Move into you build and install directory
  cd /scratch/comedi-0.7.66
• If you plan on haveing more that four cards, you need to edit the Makefile. Originally there are four devices listed to be added to the /dev directory:

  dev: -mknod -m 666 /dev/comedi0 c 98 0 -mknod -m 666 /dev/comedi1 c 98 1 -mknod -m 666 /dev/comedi2 c 98 2 -mknod -m 666 /dev/comedi3 c 98 3

  To add two more cards:

  dev: -mknod -m 666 /dev/comedi0 c 98 0 -mknod -m 666 /dev/comedi1 c 98 1 -mknod -m 666 /dev/comedi2 c 98 2 -mknod -m 666 /dev/comedi3 c 98 3 -mknod -m 666 /dev/comedi4 c 98 4 -mknod -m 666 /dev/comedi5 c 98 5

  Also, edit line 40 of include/linux/comedi.h

  was:

  #define COMEDI_NDEVICES 4

  now:

  #define COMEDI_NDEVICES 6

• To configure comedi to support the board you have (in this example it is a National Instruments board).

  ./configure

  then answer the questions

  Enter location of Linux source tree /usr/src/linux-2.4.18-27.7.x Verbose Debugging (CONFIG_COMEDI_DEBUG) [Y/n/?] Y Kernel Comedilib (CONFIG_COMEDI_KLIB) [N/m/?] n * * Hardware device drivers * in general - enter Y for the manufactorer you want and m for all the modules from that company Data Translation boards (CONFIG_COMEDI_DT) [N/y/?] n National Instruments boards (CONFIG_COMEDI_NI)[Y/n/?] y AT-MIO E series (CONFIG_COMEDI_NI_ATMIO) [M/n/?] m PCMCIA MIO E series (CONFIG_COMEDI_NI_MIO_CS) [M/n/?] m NI-DAQ-DIO24 (CONFIG_COMEDI_NI_DAQ_DIO24) [M/n/?] m PCI-MIO E series (CONFIG_COMEDI_NI_PCIMIO) [M/n/?] m NI PCI-DIO series (CONFIG_COMEDI_NI_PCIDIO) [M/n/?] m NI 670x series (CONFIG_COMEDI_NI_670X) [M/n/?] m AT-MIO-16D (CONFIG_COMEDI_NI_ATMIO16D) [M/n/?] m AT-A2150 (CONFIG_COMEDI_NI_AT_A2150) [M/n/?] m LAB-PC and compatibles (CONFIG_COMEDI_NI_LABPC) [M/n/?] m AT-AO-6/10 (CONFIG_COMEDI_NI_AT_AO) [M/n/?] m DAS08 compatible driver (CONFIG_COMEDI_DAS08) [N/m/?] n DAS16 compatible driver (CONFIG_COMEDI_DAS16) [N/m/?] n ... and many more N ... But include this one: Generic 8255 support (CONFIG_COMEDI_8255) [M/n/?] m ... N for everything else...

• make compiles comedi

• make install installs comedi into /lib/modules/2.4.18-27.7.x/comedi/comedi/

• make dev make device files (/dev/comedi0, etc. ...)

You will want to install comedilib at this point. Most of comedilib is needed for AIPs (future pages). But it also contains the startup program.

• Copy the tar-file comedilib-0.7.19.tgz to you working directory (ie. /scratch works well).
• tar -zxvf comedilib-0.7.19.tgz to uncompress and unpack it.
• edit line 40 of /comedilib-0.7.19/include/comedi.
  • to #define ?COMEDI_NDEVICES 6
• make
• make install

As root:

• cd /scratch/comedilib-0.7.19/comedi_config
• comedi_config -v /dev/comedi0 ni_pcimio

and that is it.

Some notes about comedi_config [man comedi_config]

Two useful options

• -v verbose comedi_config -v /dev/comedi0 ni_pcimio
• -r remove comedi_config -r /dev/comedi0 ni_pcimio

Some general Linux module monitoring tools

You can see all the modules runing with the tool:

/sbin/modprobe [man modprobe]

in short - to just see comedi, try:

/sbin/modprobe  -c | grep comedi
alias char-major-98 comedi
post-install cimio /usr/sbin/comedi_config /dev/comedi0 ni_pcimio 0,15
post-install ni_pcimio /scratch/comedilib/comedi_calibrate/comedi_calibrate -f /dev/comedi0

/sbin/rmmod [man rmmod]