I finally switched to kernel 2.6.7 on my Ultra-10 Sparcstation at work; the only thing that stopped me from doing this was because I couldn't get the mouse working in X under 2.6.7. I tried (and failed) so many settings under X, so I knew that something in the kernel wasn't right. Modules allways go for maximum flexibility, so I compiled the serial and PS/2 mouse drivers as modules, and activated the legacy psaux device.


After that, all was easy : modprobing the sermouse driver immediately told me that it discovered its hardware. In X, I configured the mouse as the /dev/psaux device with a PS/2 protocol.
That being solved, all my workstations are running 2.6 now.