Fuji xD and Sony Memory Stick Pro cards don't work in my Lenovo T61 with a 4-in-1 reader. However, MMC and SD cards do work.

The MMC and SD cards have drivers that are shipped with Red Hat Enterprise Linux 5.2 and later which enable them to work. At this time, the Fuji xD and Sony Memory Stick Pro cards do not have Linux device drivers and therefore will not function under Linux.