Microsoft KB Archive/826949

= Problems in Windows CE .NET version 4.1 are solved by updated common Host Controller Driver (HCD) code in Windows CE .NET version 4.2 =

Article ID: 826949

Article Last Modified on 11/18/2004

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APPLIES TO


 * Microsoft Windows CE .NET 4.2

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SUMMARY
Many problems that existed with universal serial bus (USB) drivers or with host controller code in Microsoft Windows CE .NET version 4.1 and earlier versions have been resolved by changes to the common Host Controller Driver (HCD) code in Microsoft Windows CE .NET version 4.2.

If the original equipment manufacturer (OEM) of the device uses the common HCD code from version 4.1, you will experience problems such as unrecognized devices or unresponsive devices. Instead of using the code from version 4.1, OEMs have touse the common USB code that is provided with version 4.2.



MORE INFORMATION
Although there are too many changes to the version 4.2 common USB HCD code to describe, this article describes one of the changes.

The version 4.2 USB Human Interface Device (HID) driver can create a deadlock situation if you use the common USB HCD code from version 4.1 or earlier versions. Unless you use the updated common HCD code that is provided in version 4.2, all USB is disabled. This problem is difficult to diagnose and is frequently attributed to the USB HID driver in version 4.2. However, the problem is actually in the common USB HCD code from version 4.1 and earlier versions.

Microsoft discourages device OEMs from trying to adapt earlier versions of the common USB HCD code for use in version 4.2. Microsoft encourages OEMs to link their USB HCD drivers with the common USB HCD library that is provided in version 4.2. By using the common USB HCD library, OEMs can avoid problems with the new USB HID driver and can benefit from the updated common USB HCD code.

The link to the version 4.2 common USB HCD library is at the following location:

($(_COMMONOAKROOT)\Lib\$(_CPUINDPATH)\Hcdlib.lib)

Common USB code from version 4.1 and earlier versions is not typically compatible with the common USB code in version 4.2. Microsoft encourages OEMs to always use the latest common USB HCD library instead of their own copy of the USB HCD library.

Keywords: kbinfo KB826949

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