I recently (earlier today) upgraded my system to the latest kernel release (2.2.16-3) and ran into one problem with the scsi card driver (aic7xxx). I have a adaptec 2940a PCI scsi controller and have an external jaz and zip on it.. the jaz worked fine but the zip drive refused to work correctly. I would get it mounted and could do a directory listing and may copy part of a file. then my kernel log would fill up with tim out errors (using dmesg) I hunted around and found the actual aic7xxx driver page and updated to the latest release (5.1.31) using the kernel 2.2.16-3 source tree as the base for the patch. compile the modules and copied the aic7xxx module in the /lib/modules/.... and now everything works fine...
I fixed mine by overwriting the aic7xxx files (and directory) in the source distro with the ones from RH 6.1. A pain to get ahold of them, but once I did, I then re-compiled the kernel and the aic problems went away.
I encountered the same problem and found that falling back to the 2.2.14-5.0 kernel (which comes with the RH 6.2 CDROM) also works correctly.
Newer releases had newer drivers that fixed all this. Someone just forgot to close the bug