On Thu, Aug 13, 2015 at 09:34:46PM +0200, Krzysztof Opasiak wrote: > Hello, > > On 08/13/2015 09:12 PM, Amit Pundir wrote: > >his MTP function is based on years of work originally done in the > >Android kernel tree by: > > Mike Lockwood<lockwood@xxxxxxxxxxx> > > Benoit Goby<benoit@xxxxxxxxxxx> > > Colin Cross<ccross@xxxxxxxxxxx> > > Arve Hjønnevåg<arve@xxxxxxxxxxx> > > Peter Oh<poh@xxxxxxxxxxxx> > > Greg Hackmann<ghackmann@xxxxxxxxxx> > > Badhri Jagan Sridharan<Badhri@xxxxxxxxxx> > >I've folded the series up to make it easier to review, and to provide > >a coherent patch description. > > > >Post Gingerbread (Android v2.3), Android dropped USB Mass Storage > >in favor of Media Transfer Protocal (MTP), which is widely used for > >transferring media files to digital music players and similar > >applications. This USB gadget function implements MTP functionalty. > > > >Historically this function has been a part of Android composite > >gadget driver. Android composite driver was Android's solution > >for dynamic gadget function switching prior to the ConfigFS gadget > >being merged. There were failed few attempts in past > >http://marc.info/?l=linux-usb&m=132451695808552 to upstream Android > >composite driver as well. Now this Android MTP gadget function has been > >re-implemented so as to be used as a generic ConfigFS function instead. > > > >Again, many thanks to Mike, Benoit, Colin, Arve, Peter, Greg and Badhri, > >as they are the real authors of this work. However, I've folded their > >patches together and modified it enough that I don't want them to be > >blamed for any mistakes I've made condensing their patches down. > > > >Cc: Mike Lockwood<lockwood@xxxxxxxxxxx> > >Cc: Benoit Goby<benoit@xxxxxxxxxxx> > >Cc: Colin Cross<ccross@xxxxxxxxxxx> > >Cc: Arve Hjønnevåg<arve@xxxxxxxxxxx> > >Cc: Peter Oh<poh@xxxxxxxxxxxx> > >Cc: Greg Hackmann<ghackmann@xxxxxxxxxx> > >Cc: Badhri Jagan Sridharan<Badhri@xxxxxxxxxx> > >Cc: Android Kernel Team<kernel-team@xxxxxxxxxxx> > >Cc: Greg Kroah-Hartman<gregkh@xxxxxxxxxxxxxxxxxxx> > >Cc: Jonathan Corbet<corbet@xxxxxxx> > >Cc: Felipe Balbi<balbi@xxxxxx> > >Cc: Andrzej Pietrasiewicz<andrzej.p@xxxxxxxxxxx> > >Cc: Laurent Pinchart<laurent.pinchart@xxxxxxxxxxxxxxxx> > >Cc: Yegor Yefremov<yegorslists@xxxxxxxxxxxxxx> > >Cc: Philippe Reynes<tremyfr@xxxxxxxxx> > >Cc: John Stultz<john.stultz@xxxxxxxxxx> > >Cc: Sumit Semwal<sumit.semwal@xxxxxxxxxx> > >Signed-off-by: Amit Pundir<amit.pundir@xxxxxxxxxx> > > In my humble opinion adding such function to Linux kernel doesn't make any > sense. By design, MTP is a protocol which requires access to userspace > features esp. file system. It is very important to run MTP daemon with > suitable user and LSM label and many many other issues which should be > handled by userspace access policy. > > Moreover this is not a fully functional USB function but only some interface > which can be used by mtp-responder (mtp-daemon - call it as you like) to > communicate with host. As we have FunctionFS which allows to implement any > USB function in as a userspace service. As MTP nature is more related to > userspace I think that porting MTP daemon to use this is a right way to go. > This should be much more reasonable than adding new function which also > requires daemon for proper working. So why add another interface while we > can use a generic one? Isn't there already a userspace MTP daemon that uses the existing functionfs for usb gadgets? I thought I remember seeing that somewhere... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
