I installed RH 6.1 on a computer with a Microsoft Intellimouse PS/2, so naturally I selected that as the mouse type when prompted. The mouse worked fine during the install, but didn't work in X when the system booted. I got the mouse working by changing the line Protocol "PS/2" to Protocol "IMPS/2" in /etc/X11/XF86Config. In addition, I suggest that the installer should add the line ZAxisMapping 4 5 to the Pointer section of XF86Config for wheel mice, since that line alone is enough to make the wheel work in all GTK applications.
Similar Problem: Microsoft IntelliMouse 1.1A PS/2 was dectected by the installer as a Generic 3 button. Changed this to MS IntelliMouse and installation went fine, however, once completed and booting into gnome, the mouse pointer jumped to the top right corner of the screen and couldn't be moved. Running mouseconfig and selecting Microsoft IntelliMouse (PS/2) [*] Emulate 3 Buttons updated the XFree86 config file and the next time gnome started the mouse functioned as expected. --wpb
*** Bug 6154 has been marked as a duplicate of this bug. *** The installer sets the X mouse protocol to PS/2 for an MS intellimouse. It should set it to IMPS/2 otherwise X doesnt work (mouse jumps wildly)
*** Bug 6629 has been marked as a duplicate of this bug. *** During the Mouse Configuration step, I configured my mouse as a Microsoft Intellimouse (PS/2). When the system was first brought up into run level 5, there was no mouse point. I had to drop the system into run level 3, edit the /etc/X11/XF86Config file and change the protocol from "PS/2" to "imps/2". Then the mouse worked.
*** Bug 4984 has been marked as a duplicate of this bug. ***
The installer also needs to set the mouse protocol correctly for other mouse types, for example "MouseManPlusPS/2" for some Logitech mice. Mouseconfig can set this correctly, and since the installer asks for your specific mouse type it should be fairly simple to make it set the protocol correctly in XF86Config. On a related note, it would be very nice if the installer could add the line: ZAxisMapping 4 5 if you select a mouse that has a wheel.
This is fixed in the latest installer code. Try grabbing the latest RawHide.