Hi, > > > Where in particular is the point where hcd says to hc: now do transfer!? > > In the enqueue() method when it patches the queues that > the HC will be reading (using DMA). All the HCs have > some kind of "transfer descriptors" (TDs), read by the > controller. EHCI has three different types, OHCI has two, > and UHCI has just one. The TDs go into queues. 1. I thought I made clear that I use the uhci. That was not the case. Sorry. 2. I do neither know what is the enqueue() nor do I find an identifier with that name. But if I understand you right your statement does not answer my question. I want to know where in usb-uhci.c transfer is triggered (at hardwarelevel).( in order to conclude how it is working periodically)
The anterior poster did not find out that, too. Therefore this question seems legitimate to me. So, who is going to discover the secret? (: Thanks Thomas Feldburg > > > How are the synchronisation mechanisms implemented in this context? > > That's HC-specific, look at their specs. OHCI for example > will both mark the TDs inactive and add them to a "done list" > which is reported back to the HCD. EHCI and UHCI just mark > the TDs as inactive, so they can just scan data structures > rather than needing completion IRQs. > > There are actually multiple synchronization mechanisms. > When there's a queue head (QH, or for OHCI "ED") there's > synch to link those to the controller ... and to unlink > them too. Likewise, canceling a request after it's been > handed to the HC needs special synchronization. > > - Dave > > > > ------------------------------------------------------- > The SF.Net email is sponsored by EclipseCon 2004 > Premiere Conference on Open Tools Development and Integration > See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. > http://www.eclipsecon.org/osdn > _______________________________________________ > [EMAIL PROTECTED] > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel > ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
