but still leaving the USB 2.0 Host Controller Driver compiled statically into the kernel, I get an error with the USB 2.0 driver.
Obviously this is a USB driver problem with the pvops dom 0 kernel 2.6.31 final or an incompatibility issue with the USB controller on the Intel DQ45CB motherboard. I have no issues with USB on pvops dom 0 kernels 2.6.30-rc3 and 2.6.31-rc6, and also regular kernels.
If I keep disabling the USB drivers any further, I will not be able to use USB keyboard and mouse on my system. My Intel DQ45CB motherboard does not have any PS/2 ports. But I may still be able to serial console in.