PRWIN9106003: WDEB386 V2 Command Eats Non-Maskable Interrupts

ID Number: Q73335

3.00

WINDOWS

buglist3.00 fixlist3.10

Summary:

PROBLEM ID: WIN9106003

SYMPTOMS

Under WDEB386, when the V2 command is used to disable debugger

trapping of non-maskable interrupts (NMIs), the interrupts are

"eaten" and not passed to the VMM for processing.

CAUSE

The V2 command causes an IRETD instruction to be performed for each

NMI. This was implemented to ease debugging on machines equipped

with auto-switch video boards, which generate an NMI each time the

video registers are reprogrammed and do not allow disabling this

NMI generation.

RESOLUTION

Microsoft has confirmed this to be a problem in the Windows

Software Development Kit (SDK) version 3.0. To reflect the NMI to

the VMM, use the GZ command when an NMI occurs.

This problem was corrected in the Windows SDK version 3.1.

Additional reference words: 3.00