Re: Core audio driver
Re: Core audio driver
- Subject: Re: Core audio driver
- From: Herbie Robinson <email@hidden>
- Date: Thu, 17 Feb 2005 18:40:23 -0500
At 10:04 PM +0100 2/17/05, pwicker wrote:
On Feb 17, 2005, at 9:17 PM, Mark Cookson wrote:
Be careful in your terminology here. There is NO USB Audio 2.0
Device specification (that's released to the public). There is
only a USB Audio 1.0 Device specification. There is of course USB
2.0, and you can put USB Audio 1.0 Device functionality on a device
that connects to the host over USB 2.0 and runs at high speed, but
that doesn't make it a USB Audio 2.0 device, and you will find a
couple of short comings in the USB Audio 1.0 Device specification
that limit the device's usefulness.
The problem that you are seeing is that there is a bug in the USB
stack that prevents the USB Audio 1.0 driver from working correctly
on the USB 2.0 stack. Until that is fixed, there is nothing that
the driver can do to talk to a USB 2.0 device.
Could you please elaborate on this point? I'm currently working on a
project that involves the connection of an audio/midi external USB
2.0 device (high speed needed). Until now, our plan was to rely on
the generic Mac OS X audio and midi drivers. IIRC this could be not
possible and we may have to develop our own driver :(
You are probably already aware of this, but the erata posted on AMD's
web site
(
http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_739_9004,00.html)
for the AMD-8111 chip claims that the USB 2.0 port doesn't work in
high speed mode. If your testbed has this in it, you may need to use
a PCI card.
Also, the AMD-8131 PCI-X chip has severe performance problems with
the pass-through port to the 8111. A number of users are reporting
they cannot run a single 8 channel audio interface and a hard drive
on the same 1394 bus. They are also buying PCI cards to get around
this (or buying slower machines that don't have PCI-X slots). Given
that the USB 2.0 port will be in the same place in the bus
architecture, it's probably going to be crippled on those machines,
too.
--
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