[Libdlo] Synchronous vs. asynchronous USB

[Phil Endecott]

Greg KH wrote:
> On Fri, May 29, 2009 at 11:21:47AM -0700, Bernie Thompson wrote:
>> Does anyone have datapoints on how universally libusb 1.0 is getting
>> distributed now? In particular, in terms of older Linux distros and
>> non-Linux OSes -- it'd be great to know where support stops.
>
> It's in all new Linux OS releases that are released from about a few
> months ago on.
>
>> My suspicion, given what I see in the docs right now, is we would
>> limit the portability of libdlo a little too much to take that
>> dependency right now.  But would be great to hear other thoughts.
>
> I doubt it would matter that much in the end :)

In the past I have always ended up using the direct ioctls.  It's not 
particularly complicated, though I have never tried to do enumeration 
that way; maybe that is a reason to prefer libusb.  And of course 
libusb is somewhat portable to non-Linux platforms (which?  Windows - 
but there is already a superior DisplayLink driver there; I guess *BSD 
too, right?  Do we care about that?).

I don't think we should worry about which distributions already have 
libusb 1.0; libdlo is definitely still in a "developers only" state, 
and anyone who can't install a new version of libusb (or who is 
demotivated by the need to do so) is unlikely to be installing libdlo 
at all.

Re J.King's point about locked-down Eees that can't have their libusb 
upgraded: if they can't be upgraded, then there is no way to install 
libdlo (and whatever you want to run on top of that, e.g. some new X 
driver).  If you wanted to distribute an easy-to-install package for 
such systems you could bundle a new libusb with libdlo (perhaps even statically-linked).


Cheers,  Phil.