PRB: Using Linked URBs in a WDM Driver Causes Page-Faults
Article ID: 190527
Article Last Modified on 7/22/2004
APPLIES TO
- Microsoft Win32 Device Driver Kit for Windows 2000
This article was previously published under Q190527
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: kbprb KB190527