Finally it is working, thank you for your help Kent. /dev/psaux did spit out a bunch of stuff through "cat", so I played with gpm further, specifying one by one every mouse type listed in its man page. When I've set the type to "fups2", it started working (although the same mouse was happily running as "ps2" under potato). And now there is an /proc/interrupts IRQ line for the mouse, but only when the mouse is in use. As soon as I kill gpm server, the IRQ is gone again.
Evgeny Stukalov wrote:After dist-upgrading to woody my standard ps/2 mouse is no longerrecognized (both in console and in X), even though after the upgrade gpm and XF86Config have roughly the same configuration as before. Mysteriously, the /proc/interrupts file is now missing an irq line for the mouse (it used to be irq 12 for PS/2 Mouse).