Hi Felipe, > The following two patches are RFC because we still have > a few open questions regarding them. sorry for responding so late on this patch set. I've been working on MTP for some years from the host side of the MTP pipe, with the initiator library libmtp. I would appreciate if future patch sets are CC:ed to libmtp-discuss@xxxxxxxxxxxxxxxxxxxxx where we have an MTP initiator community, thanks. The patch has some small basic problems due to it's actual paradigm/use model not being described, and that should be part of the patch so as to open up for a wider discussion. The intention of this patch is not to provide any MTP or PTP gadget drivers at all really, it is about creating a stub driver for MTP that can be used from userspace, where the actual protocol implementation is supposed to reside. So this is the PTP/MTP equivalent of TAP or TUN. This should be clear from the description of the patch and go in the comments of the file itself as well so as not to confuse anyone. The actual background to the driver being a stub is that vendors are deploying the (proprietary) MTP stack implementation from Microsoft in userspace on top of a driver like this. (This exact same work has been duplicated in a few places across the device manufacturer world.) This rationale should also be clear from the patch and the files. It is of course possible to implement a *real* MTP gadget driver in kernelspace, directly accessing the file system etc, not needing to involve userspace for any MTP transfers at all. There is an official USB IF specification for MTP which can be used to that end. Some day somebody will come along and do just that, I've been sort of hoping that some company like Google could jump in and actually do that. I know this is all absolutely crystal clear to you, but it's not going to be for everyone else in the world, that why all the words... Naming the function driver f_mtp.c is confusing since it does not implement MTP, it should be named f_mtpstub.c (and mtpstub.c) so that when someone one day really want to implement the protocol in the kernel, they can use f_mtp.c. Has the driver been designed with PTP in mind as well? There are several cameras running PTP on Linux in this world, for example the stuff from SONY. They have a userspace PTP stack in the same fashion I believe. I think it would just work with PTP as well after a quick review, but please give it a second thought. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
