On 05/24/2016 05:31 PM, Jan.Huber@xxxxxx wrote: >> You shouldn't use epX where X != 0 until you get enable event. You may >> refer to ffs-aio examples which have a suitable flag to wait for that event. > > I got the ffs-aio example (simple and multibuff) to work. > I also used the ffs-aio example as a reference and tried to get the ffs-test example to work. So I am waiting for both events (Event BIND, Event ENABLE) before accessing epX where X != 0. > However I still get the same error (-19) No such device when using ffs-test example. > > For testing I added a read()-operation to the working ffs-aio-example to make sure the endpoint descriptors are not faulty in ffs-test. Also here, I get the same error (-19). > >>From my understanding, FunctionFS is the successor of GadgetFS. It provides a file for each endpoint (ep0, ep1, ep2, ...). The endpoints can then be accessed with read() / write() operations - please correct me if I'm wrong. > > Questions remaining: > 1) Why does the ffs-test example not work even when waiting for Event BIND/Event ENABLE before accessing epX where X != 0? > 2) Is it not possible to access endpoints with read()/write() > 3) if 2) is not possible, how did ffs-test ever work? How can the endpoints be accessed now? It should be possible and this example should work. could you please test your setup with the newest kernel release? around 4.1 there was some refactoring of IO functions in functionfs. There is at least one patch which fix this[1] but I'm not sure if it will fix anything for you as you have different error code. So once again please check newer kernel. Footnotes: 1 - http://permalink.gmane.org/gmane.linux.usb.general/139316 Best regards, -- 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
