thanks a lot, this information put me on the right track. I was having problem compiling modules from the sources supplyied by the advantech compagny. There sources wasn't up to date for more recent linux version like tinycore, they were also another bug that I fixed too, finnally by changing the include file from asm/semaphore.h by /linux/semaphore.h, the modules compiled succesfully.
thanks a lot
Benoit