Hi, changbin.du@xxxxxxxxx writes: > From: "Du, Changbin" <changbin.du@xxxxxxxxx> > > Since the buffer size for req is rounded up to maxpacketsize, > then we may end up with more data then user space has space > for. only for OUT direction with the controller you're using ;-) > If it happen, we can keep the excess data for next i/o, or > report an error. But we cannot silently drop data, because > USB layer should ensure the data integrality it has transferred, > otherwise applications may get corrupt data if it doesn't > detect this case. and when has this actually happened ? Host should not send more data in this case, if it does, it's an error on the host side. Also, returning -EOVERFLOW is not exactly correct here, because you'd violate POSIX specification of read(), right ? > Here, we simply report an error to userspace to let userspace > proccess. Actually, userspace applications should negotiate no, this violates POSIX. Care to explain what problem are you actually facing ? -- balbi
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