Re: Identification of IOAudioDevice from HAL client app
Re: Identification of IOAudioDevice from HAL client app
- Subject: Re: Identification of IOAudioDevice from HAL client app
- From: Jeff Moore <email@hidden>
- Date: Mon, 11 Nov 2002 12:05:29 -0800
On Monday, November 11, 2002, at 04:48 AM, Shaun Wexler wrote:
I'd like to see two read-only properties added to the client side of
HAL:
1. Hardware Device Group 'hdgp'. Returns pointer to array[] of
AudioDeviceID, consisting of all AudioDeviceID for a particular
hardware
device, simply to allow grouping of AudioDevices without the need for a
matching method. GetPropertry returns at least one AudioDeviceID (the
inDevice's), if inDevice itself is valid.
This is along the direction for the API I'd been mulling over. It's not
on the list of "things to do next" (or even soon), however.
As an example, 'Apple Built-in'
would return two AudioDeviceID: one for input and one for output.
Wouldn't work this way. The Built-In Driver presents it's input and
output together, so there is only one AudioDeviceID for it.
The only time devices are split up are if the driver is doing something
very strange, against recommended practice (like the M-Audio Delta
10/10 driver's multiple devices), or the hardware is clocked separately
for each section like USB.
2. Transport specific reference 'trsp'. Returns (void *) to some
data
specific to type of transport, to assist in matching an AudioDeviceID
to a
hardware device in the IORegistry. Not sure of the best way to do
this, but
it should allow for different matching schemes based on transport type.
In 10.2, we added kAudioDevicePropertyTransportType which returns an
enum that says how a device is attached to the system. What would you
augment this with?
--
Jeff Moore
Core Audio
Apple
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