Configuring the Pointer Section

The mouse—called pointer in X terminology—is rather easy to set up, but you must watch out for some tricks. The main reason for this is that many vendors’ mice (e.g., Logitech) are set up to emulate other vendors’ mice, most notably Microsoft mice. Because of this, you may have to lie about your mouse.

For example, one of our test systems uses a serial Logitech Firstmouse. This mouse was designed by Logitech to emulate the Microsoft serial mouse. What’s odd is that the Logitech mouse has three buttons (a very good thing for X, as most X programs expect three-button mice), while the Microsoft serial mouse sports only two buttons.

When we configure the XF86Config file, we claim our Logitech mouse is really a Microsoft mouse (the other common choice for Logitech mice is to claim that they are Mouseman mice).

The two key things you must specify for your Pointer section is what kind of mouse, e.g., Microsoft, and what port, if it’s a serial mouse.

With this, our Pointer section is rather short:

  Section "Pointer"

     Protocol    "Microsoft"

     Device      "/dev/ttyS0"

  EndSection

Be sure to put in the type of mouse you have and the device it is connected to, rather than merely copying our configuration.

The protocol must be one of the options listed in Table 3.9.

For Logitech mice, you’ll most likely use BusMouse (if a bus mouse); for serial mice, you’ll probably use the Microsoft or Mouseman protocols, rather than the more obvious Logitech protocol. If your mouse is connected to a PS/2 port, use the PS/2 protocol. (If you’re using a newer system from a mass merchandiser like Dell, check the mouse port. Many newer systems feature PS/2 mouse ports, but they’re not always called PS/2 ports; for example, Dell calls it a mouse port.)

The Xqueue protocol is only used if you set that up for the keyboard, too. We don’t advise using this. The OSMouse is only for SCO UNIX, not for Linux.

In our case, the mouse is connected to serial port number one, often called com1 in the DOS lexicon. In true UNIX tradition, however, Linux starts counting serial ports with 0. To specify our mouse is connected to com1, we use a device name of /dev/ttyS0, the Linux device file for this port. We list commonly used ports in Table 3.10.

Your system may also have the /dev/mouse device file set up for the mouse port. No matter what device file you choose, the device must exist beforehand. (On our system, /dev/mouse is a link to /dev/ttyS0.)

The bus mouse device files are listed in Table 3.11.

Note that except for the /dev/psaux PS/2 mice, all the bus mice should use a protocol of busmouse.

There are a few more options for the Pointer section, but you’re normally better off leaving them alone. (We know; we were curious and we managed to mess things up.)

We list the other Pointer options in Table 3.12.

We generally don’t set the baud rate. When we tried to, the mouse didn’t work. If you do this, it is one time where the Ctrl-Alt-Backspace zapping sequence comes in handy.

For best results in X, you want to have a three-button mouse. Many X programs assume such a mouse.