Re: Core audio driver
Re: Core audio driver
- Subject: Re: Core audio driver
- From: selvaganesan <email@hidden>
- Date: Fri, 18 Feb 2005 15:26:56 +0530
Hi ,
Can you pls elaborate the following statement
" No, I wasn't :/ Thanks for the info. So If I sum up: high speed USB is
>
not working on the Mac because of a USB system software bug, and on PC
>
because of host controllers bug. Maybe we should reconsider a Firewire
>
connection instead of the USB. "
Does it mean that no high speed USB device cam work on Mac X ? It is really
surprising!
Any Apple person to comment on this ??????
Pls reply back ..
Thanks and regards,
Selva
----- Original Message -----
From: "pwicker" <email@hidden>
To: "Herbie Robinson" <email@hidden>
Cc: "CoreAudio" <email@hidden>
Sent: Friday, February 18, 2005 12:43 PM
Subject: Re: Core audio driver
>
>
On Feb 18, 2005, at 12:40 AM, Herbie Robinson wrote:
>
>
> 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.
>
>
No, I wasn't :/ Thanks for the info. So If I sum up: high speed USB is
>
not working on the Mac because of a USB system software bug, and on PC
>
because of host controllers bug. Maybe we should reconsider a Firewire
>
connection instead of the USB.
>
>
>
>
> 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.
>
>
>
> --
>
> -*****************************************
>
> ** http://www.curbside-recording.com/ **
>
> ******************************************
>
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Philippe
>
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>
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