Hi, On Fri, Apr 01, 2011 at 11:29:20AM -0400, Alan Stern wrote: > > Ok, thanks for the info. I'll spend some time with it during next week. > > What do you suggest in this case ? I mean, we shouldn't be doing short > > transfers with this gadget driver, right ? And if block size is always > > 512, how can we transfer one block without having a short transfer ? > > "Short" means "shorter than expected", not "shorter than the maxpacket > size". > > > Should we, then make the block size == wMaxPacketSize and keep aligning > > on a block boundary ? > > The correct approach is to align on the larger of the block size and > the maxpacket size (provided one is a multiple of the other, which > isn't always true with wireless USB!). In theory short transfers I like this approach. Will play with it next week :-) Just to be sure I understood, you mean something like: if (!(ep->maxpacket % block_size)) align = max(ep->maxpacket, block_size); else align = block_size; amount &= ~(align - 1); ??? > shouldn't occur, but it doesn't matter much if they do, provided they > are a multiple of the block size. What about controllers which can't handle Short on RX ? -- balbi -- 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
