Additional Requirements for Windows 98
In Microsoft Windows 98, a bug in the system graph builder prevents a KSCATEGORY_AUDIO_DEVICE wave-data path from operating correctly unless it contains at least one node. Because PCM pins are either hardware mixing pins (with SUM, volume, and SRC nodes, for example; see KSNODETYPE_SUM, KSNODETYPE_VOLUME, and KSNODETYPE_SRC) or have KMixer (and its nodes) inserted above them, this problem affects non-PCM pins only. In order for your driver to work on Windows 98 SE + hotfix, make sure that the data path through a non-PCM pin always has at least one node. When passing AC-3 over S/PDIF, for example, you can add a KSNODETYPE_SPDIF_INTERFACE node that implements a property to manipulate the serial copy management system (SCMS) bits in the S/PDIF digital output stream.
The earliest hot-fix package for Windows 98 SE that contains the fix to enable AC-3 playback over S/PDIF is the following:
|Hot-Fix Number||Executable File||Release Date|
All later hot-fix packages for Windows 98 SE also contain this fix.
This hot-fix package installs updated versions of the following audio system files:
The IPortClsVersion interface is not available in this hotfix, which means that this interface cannot be used to detect the presence of the hotfix.
The best way to determine whether a hotfix that contains the WavePci fixes is present is as follows:
Verify that the operating system is Windows 98 Second Edition.
Check the file version and/or date of Portcls.sys.
The WavePci fixes are present in the following the file version and date of Portcls.sys (or in any more recent version):
File Version: 4.10.2223
Date Created: 3/21/2000 8:34:03 PM
Another technique is to look in the registry to determine whether a particular hotfix has been installed. For example, you can try to access the following registry key to see whether the first hot-fix package for Windows 98 SE is installed:
The key exists only if the first hot-fix package is installed. The drawback to this approach is that it does not tell you whether a later hot-fix package, which also includes the WavePci fixes, is installed.