For the legacy CDC driver 10.10.x and earlier, the ACM control interface used the ‘Call Management’ and the ‘Union' Functional descriptors to associate itself with an ACM data interface. It does _not_ use ‘InterfaceAssociation’ descriptors. The messiness comes from the fact that if the descriptors are inconsistent with each other, the descriptor which is later wins.
For El Capitan CDC 10.11.x and later, the ACM control interface uses the ‘Union’ and ‘InterfaceAssociation’ Functional descriptors to associate itself with an ACM data interface. Any information in an ‘InterfaceAssociation’ Functional descriptor takes precedence over the ‘Union’ Functional descriptor - the logic here is that ‘InterfaceAssociation’ is a newer concept, and if you’ve implemented it, you’ve probably done the right thing. A few things to check: a) ensure that there is a ‘Union’ Functional descriptor present b) if there is also a ‘Call Management’ Functional descriptor being advertised, make sure that it’s consistent with the ‘Union’ Functional descriptor Is it possible to get a dump of the descriptors used with the problematic device? —scott > On Jul 9, 2015, at 3:36 AM, lyf4 Science <[email protected]> wrote: > > Hi Experts, > > The inbuilt CDC ACM driver is not working for the two ACM ports in the same > USB device. The driver ACM control/data is loaded for 1st interface. For 2nd > interface only ACM control is loaded and the data is failed. > > In case of single ACM port per device it works fine and driver is loaded > successfully. > > Can I get few insight on the same ? > > Regards, > Lyf > _______________________________________________ > 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/sdeandrea%40apple.com > > This email sent to [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]
