Hello, I have some trouble compiling the module p4b_smbus.o and adding support for the i2c-bus. Adding support for pci-hotplug to my kernel was successful. (reference to ticket # 1345) Here the compiler output: cc -D__SMP__ -DMODVERSIONS -include /lib/modules/2.4.20-hotplug/build/include/linux/modversions.h -D__KERNEL__ -DMODULE -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -fno-strict-aliasing -I/lib/modules/2.4.20-hotplug/build/include -c -o p4b_smbus.o p4b_smbus.c p4b_smbus.c: In function `cleanup_module': p4b_smbus.c:263: incompatible type for argument 1 of `write_lock' p4b_smbus.c:268: invalid type argument of `->' make: *** [p4b_smbus.o] Error 1 Here what setpci said: setpci -d 24C0:24C3 f2.w setpci: Warning: No devices selected for `f2.w'. Thanks for your fast respond, Alexander Pohl