Hi, Just curious, thought it would be a neat thing to do. I googled a site: http://www.bb-elec.com/product.asp?SKU=ANYWHEREUSB/5 that has a usb-over-ethernet box. I guess it's likely not to work very well for anything but constrained situations but I had been thinking that the Linux gadget driver maybe the way to do something like that, possibly with a gumstix. I guess the hub specification is specifically designed to be a hardware solution. Thanks for the comments! Cheers, Matt
> Hi Matt, > > Do you work for the government? Replacing a $1 hub chip with a $1000 > computer? :) > > More below: > >>> On Mon, 11 Dec 2006, Matt wrote: >>> >>> >>>> Hi, >>>> >>>> I'm wondering if it's feasible to implement a gadget driver that turns >>>> >>> a >>> >>>> Linux system into a hub. The hub specification in the usb spec, which >>>> >>> I >>> >>>> admit to not reading, is fairly hefty and makes me think there's >>>> probably a fair bit more to it then just proxying data to an outbound >>>> port or one of the gadget developers would have done it already. This >>>> is something I'd like to try to do so any thoughts or comments would be >>>> much appreciated. Where would one start? Cheers, >>>> >>> It isn't possible. >>> >>> > > Alan is right, it is not possible. > > The main reason is the required timings. Hubs have very strict requirements > in terms of the number of bit times things can be delayed passing through a > hub. This is so 5 hubs can be connected together in a line and the > ack/nak/stall following an EOP can still meet the required timing. > > >>> Among other problems, a full-speed hub has to be able to handle both >>> low-speed and full-speed devices attached to its downstream ports, in >>> spite of the fact that the upstream port is full-speed. If a low-speed >>> device was attached to a downstream port then the upstream port would >>> receive data at low speed, and would not be able to understand that data >>> or forward it to the downstream port. >>> >>> > > This is not true. Alan, you are confusing High speed with Full speed. All > full and low speed transactions appear on the downstream ports of all full > speed hubs. Upstream only goes up through the chain directly to the root - > what I mean is hubs don't echo downstream data that is going upstream. But > the upstream data is still sent at low speed, if that is what the device > sends. > > A PRE pid is sent to tell full speed devices that a low speed packet is > coming. This is mainly so the hubs can direct the low speed traffic > downstream. It is true that a low speed device should never see a full speed > bit stream. > > > Regards, Steve > > _________________________________________________________________ > Talk now to your Hotmail contacts with Windows Live Messenger. > http://clk.atdmt.com/MSN/go/msnnkwme0020000001msn/direct/01/?href=http://get.live.com/messenger/overview > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
