Here I am again with some news. :)

I tried last night Kernel 2.6.0 and 2.6.1 (both vanilla) and the system 
bootet up with the controller! Then I tried this:

1) unpack vanilla Kernel 2.6.9
2) copy drivers/scsi/sym53c8xx_comm.h, drivers/scsi/sym53c8xx_defs.h and 
the whole directory drivers/scsi/sym53c8xx_2/* from Kernel 2.6.1 into 
the Kernel 2.6.9 source

It booted, too. But on all this three 2.6 Kernels the SCSI-Harddisk has 
got very poor performance. With Kernel 2.4.26 and 2.4.27 it makes almost 
30 MB/s. With all three 2.6 Kernels it makes about 5 MB/s.

(see http://marc.theaimsgroup.com/?l=linux-kernel&m=109953598029428&w=2 
for detailed hardware specs and other informations)

Kernel-Config is attached to this mail.

Thanks for any idea.

Best regards,
Thomas Babut