On Thu, 22 Jun 2006, Maulik Mankad wrote: > Hi Alan and David, > > First of all let me thank both of you for replying to my mail. > > This is what the datasheet of Intel's IXP465 say for the Embedded TT. > > "IXP465 USB host supports directly connected full and low speed devices > without requiring a companion controller by including the capabilities of a > USB 2.0 high-speed hub transaction > translator. Although there is no separate Transaction Translator block in > the system, the transaction translator function normally associated with a > high-speed hub has been implemented within the DMA and Protocol engine > blocks. The embedded transaction translator function is an extension to EHCI > interface, but makes use of the standard data structures and operational > models that exist in the EHCI specification to support full and low speed > devices."
Okay. You said earlier that there are no transaction translators available; you didn't say that one is already embedded in the device. > (1) Can there be a problem in the DMA engine, which is not transmitting my > descriptor requests to the device? I do not have any programmable register > to start the DMA or to initialize it. You'd better ask Intel about that. They know a lot more than we do about errors in their devices. > Alan- > ============ > About Bus trace. > ============ > I use the Ellisys USB analyzer (hardware) to capture the USB packets on the > bus. The analyzer shows the following packets. > -> Reset > -> High Speed Detection Handshake (Timeout) [The device properly generates > the High Speed Chirp but no response from host, as the host does not support > High Speed] > -> SOF packets. > -> Suspended State > > At this point as per the bus enumeration sequence I should get the Device > Descriptor request on the bus. The USB analyzer does not capture this > request. Moreover I have traced the Linux core code for the USB and it seems > that the request gets timed out and then aborted and removed from the queue. > This is why I believe its not captured by the analyzer. No -- the reason it is not captured by the analyzer is because the controller never sends the request at all. Perhaps the EHCI driver doesn't support this controller fully, or there might be some other problem with your hardware setup. For instance, why do you get "Suspended State"? Why don't the SOF packets continue? 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 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
