<!-- This is the Linux Busmouse HOWTO.  It is mantained by Chris Bagwell 
     (cbagwell@sprynet.com)

     It makes use of the <idx> marker for good index keywrods as 
     suggested by LSL.
-->

<!doctype linuxdoc system>

<article>

<!-- Title Information -->

<title>The Linux Busmouse HOWTO
<author>Chris Bagwell, <tt/cbagwell@sprynet.com/
<date>v1.91, 15 June 1998

<!-- Abstract -->
<abstract>
This document describes how to install, configure and use a busmouse under Linux.  It lists the supported mice and attempts to answer the most frequently asked questions that come up in newsgroups and mailing lists.
</abstract>

<!-- Table of Contents -->
<toc>

<!-- Begin the document -->
<sect>Introduction.

<p>
This document is a guide to getting your <idx>busmouse</idx> working with
Linux.  With the more advanced distributions available today setting up
your busmouse is generally easy but when you do run into
problems this document will help give you a better understanding of
how to manually setup your busmouse hardware and software.

Busmouse support has been in the kernel for as long as I can
remember, and hasn't changed much in a long time, so this document
should be relevant to any version of Linux you're likely to have.

<sect1>Disclaimer.

<p>
The information in this document is correct to the best of my
knowledge, but there's a always a chance I've made some mistakes,
so don't follow everything too blindly, especially if it seems wrong.
Nothing here should have a detrimental effect on your computer, but
just in case I take no responsibility for any damages incurred from
the use of the information contained herein.

<tt>Microsoft(R) is a Trademark of Microsoft Corporation.</tt>

<sect1>Feedback.

<p>
If you find any mistakes in this document, have any comments about
its contents or an update or addition, send them to me at the
address listed at the top of this howto.

<sect1>Acknowledgements.

<p>
This howto has been, in the spirit of Linux, a community effort.
Thanks goes out to Mike Battersby, <tt/mib@deakin.edu.au/ as he
started this FAQ.  Any errors are most likely added by me.

Many thanks go to Johan Myreen for the sections on the PS/2 mice,
Robert T. Harris for help on the ATI-XL sections and Reuben Sumner
for miscellaneous info and constructive criticism.

Thanks also to the multitudes of people who have sent me mouse
information, fixes or words of encouragement.

<sect>Determining your mouse type.

<p>
There are two separate but important characteristics you will need
to know about your mouse before you go on: what mouse interface
 it uses and what <idx>mouse protocol</idx> it uses.  The interface is the 
hardware aspect of the mouse, taking into account things like which i/o 
ports it uses and how to check if it is installed.  This is the part which
the kernel is concerned with, so that it knows how to read data
from the mouse.  The protocol is the software aspect of the mouse.
Applications need to know the protocol to interpret the raw mouse
data they receive from the kernel.

<sect1>Mouse interfaces.

<p>
The Linux kernel currently supports four different kinds of bus
<idx>mouse interface</idx> : Inport (Microsoft), Logitech, PS/2 and ATI-XL.
There is no sure-fire way of determining your mouse interface --- mouse 
developers generally do their own thing when it comes to standards.  
The following sections may help, otherwise you'll just have to make it up.

<sect1>Inport mice.

<p>
<idx>Inport mice</idx> includes most of the old style Microsoft mice 
which are shaped like a bar of dove soap.  U.S. users who have purchased
Gateway computers should note that the mice that come with them
are not Inport mice but PS/2 mice (see below).  Inport mice
generally connect to an interface card which plugs into the bus
on your motherboard.  If the plug which connects your mouse cord
to the interface card is round, has 9 pins, and a notch in one
side you likely have an Inport mouse.

As far as I can tell, apart from the ATI-XL, all ATI mice
(such as those on the Graphics Ultra cards) are plain Inport
mice.

<sect1>Logitech mice.

<p>
<idx>Logitech mice</idx> in general appear almost exactly the same as Inport
mice.  They too connect to an interface card via a 9 pin mini-din
connector.  Hopefully, it will have come in a Logitech box or
have ``Logitech'' printed on the connector card so that you can
tell it actually is a Logitech mouse.

There are also some truly ancient Microsoft mice (ones with
ball bearings on the bottom as well as the mouse ball and
a DB9 connector) which also use the Logitech protocol.

<sect1>PS/2 mice.

<p>
<idx>PS/2 mice</idx> aren't really bus mice at all.  The PS/2 mouse
interface is not on an expansion card, the mouse is connected
to the PS/2 Auxiliary Device port on the keyboard controller.
A PS/2 mouse port uses a 6-pin mini DIN connector, similar to
the keyboard connector.  Many laptops also use this kind of
interface to their trackballs --- except for the connector, of
course.

<sect1>ATI combo video/mice.

<p>
<idx>ATI-XL mice</idx> are a variant of Inport mice, with some slight
differences.  They come on the ATI-XL combined video adaptor/mouse
card.  Unless you know you have an ATI-XL card (and thus an ATI-XL
mouse), you probably don't have one of these. It is possible for
ATI-XL mice to use either the ATI-XL or Inport kernel drivers,
although the ATI-XL driver should give better results.

There is also an older ATI video adaptor/mouse card called either ATI
VGA1024 or ATI VGA Wonder.  These cards are setup the same as the
ATI-XL but use the Logitech mouse protocol.  For these mice the hardware
is setup the same as for the ATI-XL but you setup the software (i.e. IRQ)
the same as the Logitech mice.

<sect1>Mouse protocols.

<p>
The PC world is full of different and conflicting mouse protocols.
Fortunately, the choice for bus mice is considerable smaller than
that for serial mice.  Most Inport, Logitech and ATI-XL mice use
the ``BusMouse'' protocol, although there are some ancient 
Logitech mice which use the ``MouseSystems'' protocol, and 
some even older Microsoft mice which use the ''Logitech'' protocol. 
PS/2 mice use the ``PS/2'' protocol.

<sect>Getting your mouse working.

<p>
Once you have figured out your mouse interface and protocol types,
you're ready to proceed.

<sect1><heading><label id="interrupt">Setting the mouse interrupt.</>

<p>
Now, you'll need to know which interrupt number your mouse is
using, and make sure it doesn't conflict with any other
peripherals you have installed.  That last part deserves to be repeated!
<bf>Make sure that it does not conflict with any other peripherals you have installed!</bf>

You should make sure that your mouse is not trying to use the same
interrupt as any of your other devices --- it is not possible for
the mouse to share an interrupt under Linux, even though it may
work fine under other operating systems.  Check the documentation
for all your peripherals to see which interrupt they use.

If you have Plug-n-Play cards, bear in mind that other operating systems
may be initializing the card to an IRQ that is not in conflict with any
other device but Linux doesn't do the same checking.  It is up to you to 
make sure there are no IRQ conflicts between all of your equipment.

In most cases IRQ4 is used for the first serial port (<tt>/dev/ttyS0</tt>),
IRQ3 for the second (<tt>/dev/ttyS1</tt>) (these are assuming you
actually have such devices --- if you don't you can happily use
their IRQ's), IRQ5 for some SCSI adaptors, and IRQ12 for some network cards.
Having a card use IRQ12 is a big problem for machines with PS/2 ports as
you are generally forced to use IRQ12 only for the PS/2 port.

For ATI-XL, Inport and Logitech mice the kernel
default is to use IRQ5, so if you are stuck with a pre-compiled
kernel (eg, CD-ROM users) you will have to use that.  If you are
using an Inport or Logitech mice with a newer kernel you may be able to
pass a command line option to the kernel to tell it what interrupt
to use without recompiling.

<sect1>Inport and Logitech mice.

<p>
If you open up your computer's case and look at the card which
your mouse plugs into, you should notice a block of jumpers
on the card (hopefully labeled ``INTERRUPT'') with positions
for interrupt (otherwise known as IRQ) numbers 2,3,4 and 5.
To change the interrupt simply move the jumper from its current
position onto the correct pair of pins.

<tscreen><verb>
***     MAKE SURE YOUR COMPUTER IS TURNED OFF   ***
***     BEFORE CHANGING THE JUMPERS AROUND!!    ***
</verb></tscreen>

<sect1>ATI-XL mice.

<p>
ATI-XL and a few other ATI busmice have a software selectable IRQ - 
you should have received with your mouse a MS-DOS program 
(<tt>VSETUP.EXE</tt>) to set the IRQ.  In order to do so you must 
(temporarily) boot MS-DOS and run this program.  Note that the VSETUP 
program takes an optional parameter ``/70'' to increase the vertical 
refresh rate (which results in less flicker).  The VSETUP program also 
allows you to select either the primary or secondary mouse address - you 
should set this to the primary address or the kernel will not be able to
detect your mouse.

Once VSETUP has been run you must perform a hard reset for the new
configuration to take effect.

<sect1>PS/2 mice.

<p>
The PS/2 mouse always uses IRQ12 -- there is no way of changing
this (except with a soldering gun.)  In the rare case that some
other device is using IRQ12, you'll have to rejumper that
peripheral to use another IRQ number.

<sect1>Configuring the kernel.

<p>
In order for your busmouse to operate correctly you will need
to configure your kernel to compile in busmouse support.  If you
are using a pre-compiled kernel then it often comes with support for
all three busmouse included.  This may still not be enough.  The kernel
could be trying to use the wrong interrupt or the detection can get
confused and treat your mouse as the wrong type.  When in doubt, 
try recompiling your kernel with only support for your mouse type and
set it to use the correct interrupt.

<sect2>Compiling the kernel.

<p>
Change to your kernel directory (here assumed to be (<tt>/usr/src/linux</tt>)
and do a

<tscreen>make config</tscreen>

If you are unsure as to your mouse type, the first time you
recompile the kernel you may wish to enable all of the busmouse
options in the hope that the kernel will autodetect your mouse
properly.  People have mixed success with this: it doesn't
always work, but on the other hand it might save you any
further compiles.

Answer ``y'' or ''m'' to the question pertaining to your type of busmouse
interface and ``n'' to all the other busmouse questions.  Use the ''m''
option if you have your system setup to support loading 
kernel modules if you do not or do not know what that 
means then it will be safe to always answer ''y'' to have the support 
directly compiled into your kernel.

As an example, if you have an Inport mouse you should answer ``y'' to

<tscreen>Microsoft busmouse support</tscreen>

and ``n'' to all other busmouse questions.  Answer the non-mouse
related questions as you usually would.

To compile the kernel with PS/2 mouse support answer ``y'' to
the question.

<tscreen>PS/2 mouse (aka &dquot;auxiliary device&dquot;) support</tscreen>

The PS/2 mouse driver actually supports two kinds of devices:
the standard PS/2 Auxiliary Device controller and a special
PS/2 mouse interface chip from Chips &amp Technologies which is
used in the Texas Instruments Travelmate and Gateway Nomad
laptops.  To compile in support for the trackballs on these
computers, answer ``y'' to the

<tscreen>C&amp;T 82C710 mouse port support (as on TI Travelmate)</tscreen>

question.  Note that you will still have to answer ``y'' to the
question about the standard PS/2 driver to even get a chance to
answer this question, since the 82C710 driver is actually an
add-on to the standard PS/2 mouse driver.

When configured both for a standard PS/2 mouse device and the
82C710 device, the driver first tries to locate a 82C710 chip
at boot time.  Failing this, the standard driver is used
instead, so using a kernel configured for both types of
interface on a machine with a standard PS/2 mouse port should
work too.  However, there has been one report of a falsely
detected 82C710 chip, so to be on the safe side do not
configure in support for the 82C710 if you don't need it.

You will now need to tell the kernel what interrupt your mouse
uses.  You can skip this step if your using a PS/2 mouse as it
always uses IRQ 12.

If you have a Logitech, Inport mouse, or an ATI mouse that uses
the Logitech protocol, edit the file
<tt>/usr/src/linux/include/linux/busmouse.h</tt> and change the line
which says

<tscreen>&num;define MOUSE_IRQ               5</tscreen>

to reflect the interrupt number for your mouse (see the section
<ref id="interrupt" name="Setting the mouse interrupt">
for details on finding your interrupt number).

If you have an ATI-XL mouse, edit the file
<tt>/usr/src/linux/drivers/char/atixlmouse.c</tt> and change the line
which says

<tscreen>&num;define ATIXL_MOUSE_IRQ         5</tscreen>

to reflect your mouse's interrupt number.

Due to the vagaries of the PC architecture, if you have set your mouse to
use interrupt 2, you must set the &num;define to use interrupt 9.

Examples

For a mouse on interrupt 3, you should change the line to read

<tscreen>&num;define MOUSE_IRQ               3</tscreen>

For a mouse on interrupt 2, you should change the line to read

<tscreen>&num;define MOUSE_IRQ               9</tscreen>

Next, compile your kernel as per the instructions which come
with it, and boot from the new kernel.  You should now have
the busmouse support correctly compiled in.

<sect2>selection.

<p>
It appears that in older kernels you had to compile in support
to use the program selection (a program that allows you
to cut and past from virtual consoles the same way you do under
X).  This option does not appear in modern kernels and the
program selection has generally been replaced with the program gpm
(see the section <ref id="gpm" name="gpm"> for more details).

If you are working with an old kernel then you may wish to set this
option to ``y'' regardless of your mouse type so that you may use the
selection program.

<sect2>Changing interrupts with newer kernels.

<p>
The steps to compile into the kernel what interrupt it uses 
works with any version of the kernel to date.  Newer kernels (starting 
somewhere in  the 2.x.x's) allow you to pass arguments to the kernel 
during load time using something like LILO or LOADLIN
to specify the interrupt number for Logitech and Microsoft Inport mice. This 
can be a real time saver as you do not need to recompiler your kernel (or know 
how to).  If you've configured your kernel to load the mouse drivers
as modules then you will need to pass this information when loading
the module.

You can add the following options to your boot line in LILO to change
interrupt:

<tscreen><verb>
bmouse=3  (Logitech Busmice)
msmouse=3 (for Microsoft Inport mice)
</verb></tscreen>

Substitute the 3 with your mouse's actual interrupt. An example of 
using this with lilo is:

<tscreen>LILO:linux msmouse=3</tscreen>

You can consult your LILO or LOADLIN docs to see how to add this type
information to their configuration files so that you do not need to type
it.

When using modules you can manually set the interrupt by using 
insmod as follows:

<tscreen><verb>
insmod msbusmouse.o mouse_irq=3    (use for Inport mice)
insmod busmouse.o mouse_irq=3      (use for Logitech mice)
</verb></tscreen>

If your system uses kerneld to auto load modules, you can edit your 
/etc/conf.modules or /etc/modules.conf file, which ever your system uses, 
and add one of the following lines.

<tscreen><verb>
options msbusmouse mouse_irq=3
options busmouse mouse_irq=3
</verb></tscreen>

<sect1>The mouse devices.

<p>
Mice under Linux are accessed via the devices in the <tt>/dev</tt>
directory. The following table gives a list of interface types
and which device you should use.

<tscreen><verb>
INTERFACE        DEVICE        MAJOR    MINOR
---------------------------------------------
Logitech        /dev/logibm      10      0
PS/2            /dev/psaux       10      1
Inport          /dev/inportbm    10      2
ATI-XL          /dev/atibm       10      3

</verb></tscreen>

<em>Note:</> If you are using your ATI-XL mouse with the Inport driver,
you should use the <tt>inportbm</tt> device, not the <tt>/dev/atibm</tt>
device.

The major and minor entries are the device numbers for that
particular device.  

If you find that you do not have these devices, you should
create them first.  To do so, execute the following as root.

<tscreen><verb>
mknod /dev/logimm    c 10 0
mknod /dev/psaux     c 10 1
mknod /dev/inportbm  c 10 2
mknod /dev/atibm     c 10 3
</verb></tscreen>

<em>Note:</> Some time in the (progressively less) recent history of
Linux the names for the busmouse devices have changed.  The following 
device names have been superceded by those above and should be removed:
<tt>bmousems, bmouseps2, bmouseatixl, and bmouselogitech.</tt>.

Many people like to create a symbolic link from their mouse
device to <tt>/dev/mouse</tt> so that they don't have to remember which
device they need to be using.  If you have one of the current
Linux distributions you will almost certainly find that you have
such a link.  If you have such a link, or create one, you should
make sure that it is pointing to the correct device for your
mouse.

<sect>Using your mouse.

<p>
This section deals with the general use of your mouse with various
applications.

<sect1>gpm.<label id="gpm">

<p>
Gpm is a program which allows you to do mouse based 'cut-
and-paste' between Linux virtual consoles, much like you can under X, and 
is a good way of testing your mouse out. The current version of gpm is
<htmlurl url="http://sunsite.unc.edu/pub/Linux/system/mouse/gpm-1.13.tar.gz"
 name="gpm-1.13.tar.gz"> and can be found at your friendly Linux FTP 
site (such as sunsite.unc.edu), and contains instructions for getting it 
compiled.  Some Linux distributions, such as Red Hat, come with a 
precompiled gpm binary.

When invoking gpm, use the -t switch to indicate which protocol your mouse 
is using and the -m option to indicate which mouse device you are using. 
Three protocols useful for most busmice are logi, bm, and ps2.  The default 
for mouse device is to use <tt>/dev/mouse</tt>, so you can omit 
the -m option if you have the appropriate symbolic link.  An example for
a Microsoft Inport mouse is:

<tscreen>gpm -t bm</tscreen>

or if you use the PS/2 protocol:

<tscreen>gpm -t ps2</tscreen>

You should then be able move your mouse and see a block move around the
screen and also be able to cut and paste text between virtual
consoles using the mouse buttons.  Read the documentation with
gpm, or do a ``man gpm'' for more information on how
to operate it.

<sect1>XFree86.

<p>
To use your busmouse under XFree86, you will need to set your
mouse protocol type in your Xconfig file. If you have a BusMouse
protocol mouse, your Xconfig should contain (including the quotes)

<tscreen><verb>
Section "Pointer"
  Protocol "Busmouse"
  Device   "/dev/mouse"
  
  # Any other options such as Emulate3Buttons
EndSection
</verb></tscreen>

For PS/2 mice change the protocol line to:

<tscreen><verb>
  Protocol        "PS/2"
</verb></tscreen>

If you have a two button mouse, it should also contain the line

<tscreen><verb>
  Emulate3Buttons
</verb></tscreen>

which will allow you to emulate the use of the middle mouse button
by pressing both mouse buttons simultaneously.
All other mouse related lines, such as ``BaudRate'' and ``SampleRate''
should be commented out, as these have no effect on bus mice.

<sect1>XFree86 and gpm.

<p>
For a long period of the kernel developement, it was not possible
to share busmice between processes.  Because of this it was hard to run 
both XFree86 and gpm at the same time. If you try to run X with gpm running 
and you get errors like the following then you know you are using one of 
these older kernels.

<tscreen><verb>
Fatal server error:
Cannot open mouse (Device or resource busy)
</verb></tscreen>

There are two meathods of getting gpm working with XFree86 with these 
kernels.  The first is to kill any copy of gpm you have running before 
you start up XFree86.  The second is to use gpm's "repeater" option
(it takes mouse data and repeats the information to multiple applications).

I would recommend upgrading your kernel if possible so that
you can share busmice between processes.  For this document, I will only 
explain the simplest meathod of using XFree86 and gpm together with older
kernels.  Please see gpm's documentation if you would like to use the repeater
meathod.

Gpm allows you to terminate running copies of itself by executing:

<tscreen>gpm -k</tscreen>

This should be done before starting up X11.  Take whatever script
you use to start up your X session, such as <tt>startx</tt>, and
add the above command to the top of the script so that gpm is 
shut down automatically.  You may wish to also put a command that
restarts gpm at the bottom of the script so that it restarts upon
exiting your X session.

<sect>Still can't get your mouse going?

<p>
So you've read through this howto a dozen times, done everything
exactly as you think you should have, and your mouse still doesn't
work?  The best advice I can give you is this: experiment.  Sure,
it's a pain in the posterior, but in the end the only way to find
out what is going to work with your mouse is to try all of the
alternatives until you have success.

As always, if there is something you don't understand, try reading
the manual page first and see if that helps.  If you have a specific
question, or a problem you think I might be able to help with, feel
free to contact me at the address listed at the top of this howto,
and I'll see if I can help you out or point you to someone who can.

The <tt>comp.os.linux.setup</tt> newsgroup or <tt>comp.os.linux.hardware</tt>
is the appropriate forum for discussion and/or questions regarding setup --- 
please don't post questions to other groups, and especially don't crosspost
questions to two or more of the Linux groups, they are more than
cluttered enough as it is!  When posting, you will get a much
better response (and much fewer flames) if you use appropriate
Subject: and Keywords: lines.  For example:

<tscreen><verb>
Subject: BUSMICE - Gateway 2000 mouse wont work.
Keywords: mouse busmouse gateway
</verb></tscreen>

</article>
