Alan Stern wrote: > On Thu, 5 Jul 2007, Mike Nuss wrote: > > There are three time periods in question. > > > > A = before there is any problem > > > > B = a read seems to have completed, the HC has advanced HeadP, but > > failed to put the completed TD on the donelist. At this point, > > something is seriously wrong, but ohci-hcd has no way of knowing > > this. > > Are you really sure about that? Isn't the HC allowed to delay updated > the donelist pointers until the end of the frame?
Yes, I've confirmed it now. After time "B", frame_no is still increasing and SOF is being generated if I enable it for a frame. > Here's what I meant. Normally SOF interrupts are disabled, but when > the driver gets a completion interrupt for an URB it could turn on the > SOF interrupt for the next frame only. Then when the next interrupt > occurs the driver could compare the ED states with the donelist, > checking for inconsistencies. What do you mean by 'completion interrupt for an URB?' > It's hard to imagine what sort of event could cause that behavior. But > hardware does some strange things. Agreed, on both. Mike ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
