I'm having a rough time trying to get kernels newer than 2.6.11 to work with my Adaptec aic7892 SCSI card to function. The problem is that I have both an Ultra160 and a SCSI 2 Wide drive connected to the card. Given the card's construction I can't plu the SCSI2 drive into the SCSI 2 port on the card without taking a razor saw to the SCSI connector and cutting a lot of it off. Anyway, because of the slower connection the card automagically derates its capabilities to the lowest common denominator, in this a 20MB/s transfer rate.
When I compile a new kernel 2.6.13 the boot process issues a "Wide Transfer Mode not found" and hangs. I've been out to the Adaptec web-site and have tried putting some CL parameters in an attempt to get more info out of the boot process so I can either send it back to Adaptec or maybe figure out what's haywire on my own.
What makes this particularly frustrating is that the driver code is exactly the same between kernel releases. I ran a diff against all files in the Adaptec subdir of the kernel code and came up with no differences. So the problem has to be some flag or function, external to the driver code itself that's causing the problem. I suspect that I'm going to learn a lot more about the Linux kernel before I get this resolved. Who knows, I might be able to submit a patch to fix the issue.