how do i know when to set callback to paged or not paged?

when using the sample code PLX9x5x for the my PCI driver it does not handle
the I/O Control request so i added new queue for the I/O Control and callback
routine PCIeEvtIoDeviceControl and added the proper code in the application
for the IOCTL.
each time i called the I/O Control request i Got the 'blue screen' after few
times
i removed the PAGED_CODE(); line and every thing worked.
the PCIeEvtIoDeviceControl routine was copied from other driver and worked
there with the PAGED_CODE();
the question: what i am missing and when to make routine paged no nonpaged?
why did it work when the routine was nonpaged? i thought that it sould be
paged?

Thanks

1. i did run PreFast on the driver it there were no issus reported there.
2. after runing !analyze -v on the dump files and the error message was
like: routine marked as was paged but should have been unpaged, when i
removed the page_code macro it started to work.
3. when reading the irql level in the PCIeEvtIoDeviceControl it show number
2 = dispatch level, the function it self contains only DbgPrint,TraceEvents
and WdfRequestComplete. nothing else.
4. is it bad that the PCIeEvtIoDeviceControl could not be paged? what the
policy on those cases? to make most code paged?

Thanks