A problem with interrupt. Please help.

In short, an DeviceOnInterrupt routine never receive control. Where to
go - that's the question.
The computer simply hangs.
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I have:

BOOLEAN DeviceOnInterrupt(PKINTERRUPT InterruptObj, pDEVICE_EXTENSION
pdx) {
ULONG intcsr;
// Read interrupt register, see if an interrupt is pending.
// If not, return FALSE immediately.
intcsr = pdx->MemoryStart[REG_CSR];
KeBugCheckEx(0x12345, intcsr, 0,0, 0); // <<<<<
if (!(intcsr & REG_CSR_INT)) return FALSE;
....
After the interrupt request is asserted by the device, computer hangs.
No "Blue screen" due to KeBugCheck!
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Any suggestions as where and how to seek for my interrupt
are greately appreciated.
Thanks a lot.

(I know for sure that DeviceOnInterrupt was successfully registered by
IoConnectInterrupt in the PnpDeviceStart routine.)