Re: code review request: simple usb stream interface (susi)
Alan Stern <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Thu, 8 Feb 2007, Edwin Olson wrote: > > >> If the host had multiple read URBs pending, would it continue to send IN > >> tokens after it had already received a short packet in that frame? > >> > > > > Yes. > > > Hmm, I've implemented the multiple outstanding URBs, but it appears that > my host only considers one read URB per 1ms period, no matter how many > read URBs have been submitted. What host controller driver are you using? > In the trace below, you'll see me creating a bunch of read URBs. My > device is spewing packets of 4 and 8 bytes as fast as it can, but the > spacing between read callbacks is still about 1ms (throughput 6kB/s on > average). So I see. Do you happen to have the URB_NO_FSBR flag turned on in your URBs? Have you tried using a USB bus analyzer to find out what's really happening? > I think I more-or-less decided it wouldn't be such a good > thing for a host to send a zillion IN tokens only to have the device > send a zillion NAKs: it'd suck up bandwidth that could be useful to > other devices on the bus. If you don't care very much about throughput, that's fine. Alan Stern ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel