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Once you have figured out your mouse interface and protocol types,
you're ready to proceed.
Now that you've found out what hardware interface your mouse uses 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!
Make sure that it does not conflict with any other peripherals you have installed!
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.
Under Linux, busmice don't register which IRQ they are using until after
they have been opened by an application that makes use of them. Plug-n-Play
hardware often registers their interrupts during bootup. This creates a
possibility for a Plug-n-Play peice of hardware to steal the IRQ away
from your mouse. Bear in mind that other operating systems
may be initialzing the P-n-P cards to an IRQ that is not in conflict
with your busmouse but things may not work out as nicely under Linux.
It is up to you to make sure there are no IRQ conflicts between all of
your equipment.
Common IRQ usage.In most cases IRQ4 is used for the first serial port (/dev/ttyS0),IRQ3 for the second (/dev/ttyS1) (these are assuming youactually have such devices --- if you don't you can happily usetheir IRQ's), IRQ5 for some SCSI adaptors, and IRQ12 for some network cards.Having a other card use IRQ12 is a big problem for machines with PS/2 ports asyou are forced to use IRQ12 only for the PS/2 port.For ATI-XL, Inport and Logitech mice the kerneldefault is to use IRQ5, so if you are stuck with a pre-compiledkernel (eg, CD-ROM users) you will have to use that. If you areusing an Inport or Logitech mice with a newer kernel you may be able topass a command line option to the kernel to tell it what interruptto use without recompiling.
Inport and Logitech mice.
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.
*** MAKE SURE YOUR COMPUTER IS TURNED OFF ***
*** BEFORE CHANGING THE JUMPERS AROUND!! ***
ATI-XL mice.
ATI-XL and a few other ATI busmice have a software selectable IRQ -
you should have received with your mouse a MS-DOS program
(VSETUP.EXE) 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.
PS/2 mice.
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.
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.
In pre-2.4 series kernel there is no support for auto-detection of
the IRQ that a busmouse is using. Therefore, if your card is set to
anything but the kernel default value of IRQ 5 then you will need to
let the kernel know what IRQ to use instead. This can be done in one
of two ways. The easiest is to pass command line options to the kernel
during the bootup process. Please read thru the "Compiling the kernel"
section for reference but attempt the directions in "Changing interrupts
with newer kernels" first. Also of great help in this area is the
Bootprompt-HOWTO, avaliable at most sites that carry this HOWTO.
Compiling the kernel.
Change to your kernel directory (here assumed to be (/usr/src/linux)
and do a
make config
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
Microsoft busmouse support
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.
PS/2 mouse (aka "auxiliary device") support
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 & 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
C&T 82C710 mouse port support (as on TI Travelmate)
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
/usr/src/linux/include/linux/busmouse.h and change the line
which says
#define MOUSE_IRQ 5
to reflect the interrupt number for your mouse (see the section
Setting the mouse interrupt
for details on finding your interrupt number).
If you have an ATI-XL mouse, edit the file
/usr/src/linux/drivers/char/atixlmouse.c and change the line
which says
#define ATIXL_MOUSE_IRQ 5
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 #define to use interrupt 9.
Examples
For a mouse on interrupt 3, you should change the line to read
#define MOUSE_IRQ 3
For a mouse on interrupt 2, you should change the line to read
#define MOUSE_IRQ 9
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.
Changing interrupts with newer kernels.
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:
bmouse=3 (Logitech Busmice)
msmouse=3 (for Microsoft Inport mice)
Substitute the 3 with your mouse's actual interrupt. An example of
using this with lilo is:
LILO:linux msmouse=3
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.
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.
options msbusmouse mouse_irq=3
options busmouse mouse_irq=3
Mice under Linux are accessed via the devices in the /dev
directory. The following table gives a list of interface types
and which device you should use.
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
Note: If you are using your ATI-XL mouse with the Inport driver,
you should use the inportbm device, not the /dev/atibm
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.
mknod /dev/logimm c 10 0
mknod /dev/psaux c 10 1
mknod /dev/inportbm c 10 2
mknod /dev/atibm c 10 3
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:
bmousems, bmouseps2, bmouseatixl, and bmouselogitech..
Many people like to create a symbolic link from their mouse
device to /dev/mouse 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.
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