Hibernation problem with WDM USB to serial driver

Hi,

I have developed a WDM USB to serial (virtual COM port) driver. It it
working fine during power on/off, reboot, suspend and resume. The problem
arises when the system goes into the S4 (hibernation) state when an
application such as Windows hyperterminal is holding on to a virtual COM
port. When the system resumes from hibernation, the driver is unable to
load properly during the renumeration process (a yellow exclaimation mark
is seen in the device manager window). Can someone please advise me what I
can do to solve the problem. Have I not handled some power management IRPs
or have missed out certain things in my driver?

Thanks and Best Regards
Linus


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