There are two separate but important characteristics you will need to know about your mouse before you go on: what hardware interface it uses and what mouse protocol it uses.
The hardware 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. For serial mice users, this part of the story is easy since their interface is always the serial port device drivers.
The mouse 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 device driver.
The Linux kernel up to the 2.2 series supports four different kinds of busmouse hardware interface : Inport (Microsoft), Logitech, PS/2 and ATI-XL.
The 2.4 series of kernel also includes support for several new busmice including an IBM PC110 digitizer pad and Apple Desktop mouse. It also contains drivers for USB mice which are sometimes discussed with busmice since they fall outside the more common serial driver interface.
There is no sure-fire way of determining your hardware interface. For those that have Windows 9x install, it sometimes helps to go to the Systems screen under the control panel and look for devices controlling your mouse. This screen will often tell you the interface type and what I/O ports and interrupts this hardware uses.
Inport mice include most of the old style Microsoft mice which are shaped like a bar of dove soap. 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.
ATI currently claims that all ATI VGA + Busmouse combo cards used the Microsoft Inport hardware and thus owners of these cards should first attempt using the Microsoft Busmouse driver.
The ATI-XL VGA+Busmouse card technically is compatible with the Microsoft Inport mouse driver but has slightly different provisioning for interrupts and therefore has a specific driver for it. Avoid this driver if possible since its not supported very well.
Logitech mice 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.
The PS/2 mouse interface is not on an expansion card, the mouse is connected to the PS/2 port on the keyboard controller. This is sometimes located on the keyboard or more often as a extra port somehow connected directly to the computer case.
A PS/2 port uses a 6-pin mini DIN connector, similar to the keyboard connector. Many laptops also use this kind of interface to their trackballs or touchpads; in this case the mouse is internally connected to the PS/2 port and needs no connector.
ATI-XL mice are a variant of Inport mice, with some slight differences in interrupt setup. 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 drivers are setup the same as for the ATI-XL but you setup the software the same as the Logitech mice.
The IBM PC110 palmtop contains a digitizer pad that can be used to emulate a mouse using the PS/2 mouse protocol. In this case, you set up the hardware interface using the IBM PC110 device driver and setup software as you would a PS/2 mouse.
This bus mouse is common on Macintoshes and uses a 4 pin connector. The hardware is controled by the kernel but application software will need to be aware of its unique mouse protocol. I am currently unaware of what protocols this mouse uses.
The period of time that busmouse were popular, the hardware companies were experementing alot and cross-licensing each others designs. Therefore, you could have a ATI mouse that uses the Logitech hardware interface or a Logitech that uses the Inport interface. If you know you have a busmouse but can't get it working with the standard interface/protocol setups, try experementing by using different interface device drivers with different mouse protocols.
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 will always use the ``PS/2'' protocol.