No more Windows call-back to our InterruptServiceRoutine on Intel V2 processors

Hi,

I have currently a problem on Intel V2 processors that does not happen
on V1 processors.

Our PCIe device is still able to generate interrupts (confirmed with a
logic analyzer) but our InterruptServiceRoutine is no more called back
by Windows.

This problem happens after 7-8 days of normal behaviour (an interrupt
occurs at each 4ms).

Does anybody have seen this before?

What can cause this InterruptServiceRoutine call-back problem?

Additional information:

OS: Windows 7 x64 SP1.

Interrupt: legacy mode.

Processor: Intel Xeon E5-1650 V2

Thanks for your help!

Sebastien