Re: 'Ganged' or 'Linked' Hardware
Re: 'Ganged' or 'Linked' Hardware
- Subject: Re: 'Ganged' or 'Linked' Hardware
- From: "B.J. Buchalter" <email@hidden>
- Date: Fri, 18 Apr 2003 13:42:13 -0400
on 4/18/03 1:10 PM, Matthew Xavier Mora at email@hidden wrote:
>
Maybe CoreAudio can add a property for kexts to publish which is a
>
"linkable" property. This property could contain either a class name,
>
or a list of GUID's that this device can link to. So when multiple
>
Mobile I/O's are plugged in, each instance can publish this property.
>
In Audio midi setup the user can then link or unlink them with the
>
direction of the link establishing master/slave relationship. It
>
could be a read only property describing to the user the link setup
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if the driver has its own set up app. Also you could link the input
>
of one device to the output of other devices so that they could run
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in sync.
>
>
The fact that this would be a standard property (instead of each
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driver coming up with its own way to do it) would mean that the pref
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would be saved and restored automatically by the system. The issue is
>
that kext don't really have an easy way to save off preferences so
>
it's nice to get help from CoreAudio.
Right. I guess that if there is no standard property for this, it could
still be implemented as a HAL plug-in for the property. But then AMS would
not show it, so it would still only be supported by a vendor provided
control app. The lack of persistent preferences for kexts is definitely one
big issue in all of this.
The second big issue is that (unless I am missing something) the current
implementation of the HAL and Sound Manager are not taking advantage of the
stream enable properties in the HAL. Currently we have a big enough problem
with 18in/18out devices chewing up the CPU when playing iTunes since iTunes
(presumably through the sound manager) is actually running all the streams
in both directions just to play stereo. If we start healing devices, then we
could presumably see linked devices that publish 60-100 streams or channels
in both directions. To use one of these devices to play a stereo output will
be crazy. We really need to have ALL CA clients use the stream enables (both
Sound Manager based and HAL based), and we need CA to respect them.
Otherwise, big I/O devices appear to the user to be really inefficient.
Best regards,
B.J. Buchalter
Metric Halo
M/S 601 - Building 8
Castle Point Campus
Castle Point, NY 12511-0601 USA
tel +1 845 831-8600
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