Miscellaneous Installation Issues for an Audio Adapter

Listed are the most common installation issues for an audio adapter:

  • During initial installation of an audio device or when undergoing an operating system upgrade that destroys existing audio settings, the driver should ensure that the settings are initialized to reasonable default values. For more information, see Default Audio Volume Settings.

  • Sometimes during installation, an OEM would like to override the default audio volume level, or the default microphone boost level that is hard-coded by the Audio Class driver. This was not possible in earlier versions of Windows up to Windows 7. In Windows 8 and later, you can now customize the default values for these settings. For more information about how to do this, see Customizing Default Audio Volume Settings.

  • In Windows Vista and later operating systems, the default setting for the master volume level of an audio device is six decibels of attenuation, and it is set at the time of installation. This default master volume level setting, or any other level that you choose after installation, is maintained no matter how often you restart your computer. To opt out of volume level persistence you can use the AddProperty registry directive via an INF file, to set the value of the PKEY_AudioDevice_DontPersistControls registry key. For more information about how to do this, see Opting Out of Volume Level Persistence.

  • During an operating system upgrade, an audio device's installed driver and registry settings can frequently be preserved. For guidelines on how to make this process transparent to users, see Operating System Upgrades.

  • Windows 2000 limits the number of device interfaces that can be exposed through the following Windows multimedia APIs: waveIn, waveOut, midiIn, midiOut, mixer, and aux. For more information, see Windows 2000 Device Interface Limits.

  • When installing a driver in Windows Me/98, INF files are restricted to a size of 64K bytes and INF section names are limited to 28 characters. Windows 2000 and later are not subject to these restrictions. Any INF file that is to be used both in Windows 2000 and later and in Windows Me/98 must meet the stricter limitations of Windows Me/98. For more information, see Creating INF Files for Multiple Platforms and Operating Systems.

  • In Windows Me/98, the total number of characters in all the multimedia device ID strings in an INF file, including terminating zeros, must not exceed 200. INF files are not subject to this restriction in Windows 2000 and later.

  • An audio driver is easily designed to allow multiple identical instances of an audio adapter card to be plugged into the same system. For more information, see System-Wide Unique Device IDs.

  • For a list of INF file keywords that are common to all device classes, see INF File Sections and Directives. However, this list does not contain several media-specific keywords. For more information, see Media-Specific INF File Keywords.

  • For information about how an adapter driver or miniport driver can obtain setup information from the registry, see Retrieving Device Setup Information.

  • For information about Windows Vista support for an audio adapter which does not have a physical volume control knob, see the Windows Vista Software Volume Control Support topic.

  • Only Windows Me/98 supports the UseFDMA flag. In these operating systems, the [WDMAUDIO.FDMA] section in the Wdmaudio.inf file sets the UseFDMA flag in the registry, causing the DMA controller to be configured to perform Type-F DMA transfers. If a proprietary INF file needs to set this flag, it does so by including Wdmaudio.inf and invoking the [WDMAUDIO.FDMA] section of that file.

    Windows 2000 and later (including the 64-bit versions of Windows) ignores the UseFDMA flag, and the [WDMAUDIO.FDMA] section in their Wdmaudio.inf files does not load this flag into the registry.

  • Windows 98 does not support the following:

    The INF file for a port-class audio adapter (see Introduction to Port Class) that uses the above functionality should not install the driver in Windows 98. See Installation Issues for an Audio Driver in Windows 98.

  • Windows 98 Second Edition (SE) does not support the full functionality of a WavePci miniport driver. In Windows 98 SE, installation of a port-class adapter driver with a WavePci miniport driver is driver-specific.



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