Re: audio kext plugin
Re: audio kext plugin
- Subject: Re: audio kext plugin
- From: Matt Gonzalez <email@hidden>
- Date: Mon, 04 Nov 2002 16:45:08 -0800
- Organization: Echo Digital Audio Corp.
Well, since the topic came up...
Our driver uses just such a plugin. Overall, it works fine, on both 10.1 and 10.2.
There is however, one issue - AudioDriverPlugInClose is never called, on either 10.1 or
10.2. Everything else works swimmingly.
Also - do I need to provide my own synchronization inside the plugin, or is it already
thread-safe?
Thanks!
Matt
Jeff Moore wrote:
>
A few fun facts about the plug-ins defined in
>
<CoreAudio/AudioDriverPlugIn.h>:
>
>
- The API is there to allow drivers to point the HAL at a bundle that
>
provides the implementation of properties over and above those
>
documented in <CoreAudio/AudioHardware.h> through the HAL's API.
>
- Only the driver for a device can specify the bundle to use.
>
- The path to the bundle is specified in the IO registry entries for an
>
IOAudioDevice or IOAudioEngine in kIOAudioEngineCoreAudioPlugInKey as a
>
relative path from /System/Library/Extensions.
>
- The plug-ins are raw CFBundles that export the entry points listed in
>
the header, rather than being CFPlugIns or Components.
>
- There is no documentation save what is in the header and the brief
>
mention in the "Writing Audio Drivers" pdf.
>
- There is no sample code.
>
- There were bugs in the HAL that prevented these plug-ins from working
>
too well prior to 10.2.
>
- I'm happy to answer questions.
>
>
On Monday, November 4, 2002, at 12:18 PM, Mark Ketilson wrote:
>
>
> I am a new apple developer and I am beginning to write a USB audio
>
> device plugin to control some of the extra device features. I've
>
> looked at AudioDriverPlugIn.h and at AudioHardware.h but I'm having
>
> trouble getting a good start. If someone could direct me to an
>
> example or some documentation that would be super helpful. I've
>
> looked briefly at the CoreFoundation documentation on plugins but they
>
> seem to apply more to applications... are things different for kext
>
> plugin's? Also, would the midi plugin examples be a good template?
>
>
--
>
>
Jeff Moore
>
Core Audio
>
Apple
>
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