Hi, > -----Original Message----- > From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb- > owner@xxxxxxxxxxxxxxx] On Behalf Of Marco Zamponi > > Hi! > Sorry, I posted before but forgot the subject. > I am running the test application "ffs-test.c" in user space and I > want to > write the descriptors to ep0. > However, it seems that I can only write interface descriptors > and enpoint descriptors. > What about device and configdescriptors? When I put those in the > "descriptor" struct I get an EINVAL (22, invalid parameter) error: > > "ffs-test: info: ep0: writing descriptors" > "ffs-test: crit: ep0: write: descriptors: (-22) Invalid argument" This is intended behavior. FunctionFS is kernel-userspace interface which allow to provide implementation of *single* usb function (interface). Each usb device consist of several functions which are placed in configuration. FunctionFS allow you only to provide descriptors for this *one particular* function which is implemented by you. Information related to whole usb device may be set using two ways: 1) Using ConfigFS to create your own gadget [1] 2) Using modprobe g_ffs and provide arguments which are suitable for you. ConfigFS is more flexible and will allow you to set all values from usb device/configuration descriptors using file system. Footnotes: [1] https://wiki.tizen.org/wiki/USB/Linux_USB_Layers/Configfs_Composite_Gadg et -- BR's Krzysztof Opasiak Samsung R&D Institute Poland Samsung Electronics -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
