Re: Native mode IO problems (Jeff Moore)
Re: Native mode IO problems (Jeff Moore)
- Subject: Re: Native mode IO problems (Jeff Moore)
- From: Jeff Moore <email@hidden>
- Date: Wed, 3 Feb 2010 17:21:13 -0800
It may be true that there are other devices sharing the USB controller with a given USB port. But the sort of problems that this would cause do not seem to me would result in the sort of problems that Mr. Booth was describing with regard to using floating point samples or integer samples. At least that's my take on it. Hence my request that he file a bug with us about it since the driver in question is one of the ones we supply.
On Feb 3, 2010, at 4:22 PM, Gordon Rankin wrote:
>>
>> Date: Tue, 02 Feb 2010 19:32:02 -0800
>> From: Jeff Moore <email@hidden>
>> Subject: Re: Native mode IO problems
>> To: CoreAudio API <email@hidden>
>> Message-ID: <email@hidden>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Interesting. This behavior still doesn't sound right to me. At the very least, it isn't the greatest customer experience.
>>
>> So, it is still probably worth filing a bug about this issue.
>>
>> On Feb 2, 2010, at 7:26 PM, Paul Davis wrote:
>>
>>
>>> > On Tue, Feb 2, 2010 at 10:23 PM, Stephen F. Booth <email@hidden> wrote:
>>>
>>>> >> For reasons that I can't explain, if I swap the DACs the
>>>> >> problem swaps also. If I plug both DACs into the port on the right
>>>> >> side then everything works properly for both.
>>>> >> >> I've no idea what the difference in USB ports is, but I'm happy
>>>> >> everything is working at this point. Sorry to pollute the list.
>>>>
>>> > > this is actually a sort-of well known problem with a variety of USB
>>> > audio interfaces. my recollection is that it relates mostly to the
>>> > power supply delivered to the various ports. it affects non-Mac
>>> > systems too, but i'm suprised to hear of it on a mac - i had the
>>> > impression that the ports were all symmetric.
>>>
>>
>>
> Jeff,
>
> Gordon here I designed the Proton and wrote the USB Asymchronous code for it. Actually I thought Stephen was using the same USB port or I would have indicated the same thing we have found that not all USB ports are created equal.
>
> Those ports that share internal devices (i.e. internal hub, like bluetooth, mouse pad, camera etc...) will always have more trouble streaming Audio data as compared to ones that are directly to the hub.
>
> Stephen, Centrance corp wrote the software in the Benchmark unit if you need info on that you may want to contact Michael Goodman. He maybe on this list, I don't know.
--
Jeff Moore
Core Audio
Apple
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