Re: [PATCH/RFC 5/5] usb: Add support for streams alloc/dealloc to devio.c

Amit Blay
2011-08-21T10:18:45Z

Thanks Sarah, Hans for your comments,

On Thu, August 18, 2011 3:47 pm, Sarah Sharp wrote:

> Yes, I think this is the correct solution. Sorry for taking so long to
> get back to you.

OK, so I will go ahead with implementing this solution.

> On Wed, Aug 17, 2011 at 09:06:03AM +0200, Hans Petter Selasky wrote:
>> I would suggest overloading the "unsigned int pipe", instead of breaking
>> existing API's by adding a new stream ID value. Also for LibUSB.

The purposed solution will not break any existing API, by doing the
following:
a. Adding a new API for streams alloc/dealloc
b. Adding a new API for submitting a URB which is stream capable (I will
implement this in a separate patch).

> I don't see this as a strong argument why we should arbitrarily limit a
> new API. It's very hard to deprecate kernel to userspace API, so I
> think we should do it right the first time. There are current
> applications (like an SSD behind a UAS device) that need as many
> concurrent streams in flight as possible, so I don't buy the argument
> that there aren't current applications that need that many streams.

I agree with Sarah.
Hans, I appreciate your inputs. Please let me know if you see a good
reason why not implementing the new APIs purposed above for streams
allocation and usage. Otherwise I will go ahead with the implementation.

Thanks,
Amit.

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