Oh, and I really like threads... On Tue, Sep 21, 2010 at 3:39 PM, Daniel Ferguson < danieljayfergu...@gmail.com> wrote:
> Thank you for asking these questions. > > The motivation was to further simplify the interface, whilst maintaining > sensor generic-ness. > And then the plan, barring course changing discussions, would be to build a > sensor specific layer on top of that. > > My main reason for threads is so read requests can be continually > submitted, and the process to be transparent. > In using libusb with isochronous transfers, in conjunction with the > scenario written below, I have to submit many read requests in order to > keep up with the data coming from the device. So, this code abstracts that > away. > > I can't justify why there is a writer thread.. > > The scenario: > Testing has been with device side code that continually increments a value > and sends it. > the incremented value is 4 bytes, and is within a 128 byte isoc packet(up > to 1023 bytes). The idea that there are "isoc packets" and "sensor packets", > where the former can be much larger than the latter creates an idiom where > each isoc packet is a batch in an of itself. By leveraging that, my > justification for reader threads could be moot depending on sensor packet > sizes and sampling rates. > > Finally: > Let's say, which is more or less true, that we have no isoc infrastructure, > other than a few light hearted examples in the repo. > I'd like to hear some ideas on how to go about building the infrastructure > to accomplish end to end communication. > I'd like to continue moving this effort forward in a way that fosters > round-table discussions and motivated by general consensus. > I expect replies...or else... i'll continue in my wayward direction. > > P.S.: > Realistically, the effort I have put in may have yielded no result other > than an increased understanding by me. > I consider that a big win. > > Cheers, > Daniel > > > > > > > > > > > > > On Tue, Sep 21, 2010 at 1:53 PM, ja...@minilop.net <ja...@minilop.net>wrote: > >> Hello! It looks like you're building an interface for high-performance >> isoc transfers, so that's cool. I don't understand what motivated it >> though, so I have a couple of questions. >> >> What led you to choose creating a thread for reads and writes? On >> reviewing the libusb 1.0 documentation it looks like the asynchronous >> API does everything I think you want without worrying about >> synchronizing across threads; so what did I miss? >> >> What difficulty did you encounter in using libusb that you're trying >> to solve with a higher-level abstraction? Is there some way libusb >> could be improved that would be easier than writing and maintaining a >> separate library? >> >> Thanks, >> Jamey >> > >
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