> On Feb 25, 2015, at 16:09 , Roland King <[email protected]> wrote: > > >> On 26 Feb 2015, at 04:00, Rick Mann <[email protected]> wrote: >> >> I'm trying to help out an open source project called BBBlfs >> (https://github.com/ungureanuvladvictor/BBBlfs). Their code allows the user >> to write a BeagleBone Black's (popular single-board computer) on-board flash >> storage from Linux (and hopefully OS X). >> >> Unfortunately, because the BBB shows up as a CDC device, the Apple CDC >> driver claims it. They need a codeless KEXT to prevent that. > > Are you sure about that? Does the device only present itself as a CDC device > or does it have a number of interfaces one of which actually really is a CDC > device but also contain other custom endpoints? That’s fairly common as the > CDC device piece is usually hooked up to send serial data to and from the > board, but there are other interfaces on there as well to do other things. > > If so then the CDC driver will claim the CDC device endpoints only and > present them as a normal serial device, but won’t claim any of the other > endpoints which aren’t related to CDC, leaving other processes free to use > them. This is usually what you want, you want the CDC device to be a > supported serial device and the custom endpoints to be available for their > custom purposes. > > One common issue with this has nothing to do with the CDC drivers, but has to > do with code which uses libusb, or libusb-derived code, to use the other > endpoints, the non-CDC ones, on the same device. The libusb code tries to > open the device and read it to find the other endpoints. That doesn’t work > because the device itself has already been opened by the CDC driver, > exclusively, so that code to re-open it fails. However you don’t need to open > the actual device to find the endpoints on OSX, you can discover them with > IOKit, and they are perfectly usable. > > Is that the case here?
Might be, thanks for the note; I'll look into it. -- Rick Mann [email protected] _______________________________________________ Do not post admin requests to the list. They will be ignored. Usb mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/usb/archive%40mail-archive.com This email sent to [email protected]
