PRB: Using Linked URBs in a WDM Driver Causes Page-Faults

ID: Q190527

The information in this article applies to:

• Microsoft Win32 Device Driver Kit (DDK) for Windows 98

SYMPTOMS

The USB Request Block (URB) structure, which a WDM driver uses to submit a request to a USB device, defines an "UrbLink" element that is intended to allow the driver to submit a linked list of URBs to the WDM USB driver stack. When you use this field with the WDM USB driver stacks shipped in Windows 98, Windows 95 OSR 2.1, and Windows 95 OSR 2.5, a system failure such as page-fault to typically occurs.

CAUSE

The WDM USB driver stacks shipped in Windows 98, Windows 95 OSR 2.1, and Windows 95 OSR 2.5 do not provide any support for linked URBs.

RESOLUTION

A WDM driver must never submit linked URBs to the WDM USB driver stack when running under Windows 98, Windows 95 OSR 2.1, or Windows 95 OSR 2.5. The UrbLink element of the URB must always be NULL.

STATUS

This behavior is by design.

Additional query words: WDM USB UrbLink URB

Keywords          : kbDDK kbWinOS98 
Issue type        : kbprb

Last Reviewed: August 5, 1998