INFO: Prevent Adapter Unbind on Suspend (320939)

SUMMARY

A miniport driver can inform network driver interface specification (NDIS) through a registry entry on the target device not to register the adapter with the power management module.

To do this, you can use the following registry entry:

HKEY_LOCAL_MACHINE\Comm\Adapter Instance\Parms\DisablePowerManagement
DWORD:1

where Adapter Instance is the instance name of the adapter in question (for example, NE20001).

MORE INFORMATION

By default in Windows CE .NET, every NDIS adapter is registered with the power manager module. When the device is suspended, the Windows CE .NET power manager sets the power level to D4 for each of these adapters. If the miniport driver supports power management, the request is passed to the miniport; otherwise NDIS unbinds the adapter from all of the protocol drivers.

The advantage of this is that Networking Connection Manager can set the power level of any adapter to D4 to disable the adapter. For a miniport that supports power management, this request is passed to the miniport. Typically, this results in the miniport powering down the adapter. For a miniport that does not support power management, NDIS unbinds the miniport driver from the protocol drivers.

However, some protocol drivers are not designed to handle the unbinding process. For example, the Infrared Data Association (IRDA) protocol driver may cause the system to appear to stop responding (hang) when the device is suspended.

You can use of the registry key that is listed in the "Summary" section to prevent the unbinding process.