[Nut-upsdev] ups_set_altinterface() breaks tripplite_usb on Mac OS X

Charles Lepple clepple at gmail.com
Thu Sep 3 03:42:37 UTC 2009

Is there a particular reason why we are setting the alternate
interface to 0 in drivers/libusb.c?

I have seen some documentation which indicates that this should
already done by the OS when the device is enumerated. If that is the
case, then there is no reason why we should hardcode the alternate
interface to 0.

If I remove the following code, tripplite_usb seems to work*:

                        /* set default interface */
                       usb_set_altinterface(udev, 0);

Any objections to removing this? Can I get some volunteers to try this
out on their non-OS X systems?

I am using libusb-0.1.12 on Mac OS X 10.5.8.

* I did have to monkey with a codeless kext in order to allow libusb
to claim the device. However, it doesn't seem like OS X allows you to
bypass the claim operation anymore.

- Charles Lepple

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