Ideas sought on OSX USB problems

[JamesF]

(Not entirely sure this is in the right place, but it seems the best fit...)

I have written a driver for the Neximage Burst cameras to add support for them in oaCapture this month, but I've run into a bit of an issue and I'm not sure how to progress at this point.  I'm hoping someone with more experience coding OSX might be able to help.

The code I have written is layered on top of the latest release of libusb and works fine on Linux when the (USB2) Neximage camera is connected either via USB2 or USB3.  It works on my Mac Mini that has USB2, on both Snow Leopard and Yosemite.  In fact, if I build the executable on Snow Leopard it also works on Yosemite.

However, if I try exactly the same code on my MBP (13" 2013), also running Yosemite, I get a couple of frames arrive at most and then the entire USB subsystem seems to get wedged, to the point where the trackpad stops functioning and plugging in an external mouse doesn't help.  I can log in remotely and use the machine though, so clearly the machine hasn't completely crashed.

Plugging the camera into a USB2 which is then connected to the MBP doesn't work either.  Neither binaries built on Snow Leopard or Yosemite on my Mac Mini work.

When I reached this point I was about to conclude that it was a strange hardware issue, but then I had the idea of booting the MBP into Linux off a USB stick and running oacapture inside that.  I've done that and the camera connects ok and is currently absolutely rock solid delivering 25fps at 1280x960.

In all cases the OSX releases are fully up-to-date (eg. 10.10.5 for Yosemite).

I also have a user-space UVC driver that I've bodged to deliver images from the camera though it isn't viable for anything more than testing.  I didn't write most of that -- it's someone else's open source project that I contributed some work to.  Using that driver for the same camera fails in exactly the same way as my own driver.

I don't like to push failures off onto other people's code as history shows that it's generally me who has messed up, but having done the test with Linux on the MBP I'm struggling not to see this problem as most likely to be some sort of software issue with OSX and USB3 and I'm now out of my depth without much in the way of a floatation aid.  Does anyone have any ideas about how I might progress further in tracking the problem down?

James