On Saturday 12 February 2005 2:03 pm, Alan Stern wrote: > On Sat, 12 Feb 2005, Mark McClelland wrote: > > > What happens if the last URB submitted for the frame is only 20667 > > bytes, or whatever (frame_length % max_urb_size) is? I wonder if the > > firmware just isn't able to pad-out partial bulk packets reliably? > > That's not how it works. The firmware never has to pad partial packets; > it just sends whatever it has whenever the host asks it to. The host asks > for each packet individually, and the camera sends a full packet if it has > that much data, otherwise it sends a partial packet.
Moreover, this isn't Windows: there's no "max urb size"! If you can allocate multi-gigabyte buffer, USB will do its best to handle it. And if there's enough memory for the transfer descriptors, it will actually succeed... Any progress on providing that additional information I described the other day? It's fine if folk are having a good time speculating about what's wrong, but I usualy find facts more interesting ... - Dave ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
