2011/6/2 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>: > On Thu, 2 Jun 2011, Soho Soho123 wrote: > >> Dear Alan, >> >> >> My meaning is : >> is there any time time inaccuracy acceptable in ehci host??? > > I don't understand this question. Soho: is there any tolerance of index for iso schedule? > >> Or any blind spot from iso schedule check criterion? > > If there is any blind spot in the iso scheduling code, I don't know > about it. Otherwise I would have fixed it! > >> Since we do not familiar with ehci host iso schedule algorithm. When >> we update ehci host and usb subsystem code to 2.6.39 version, the >> slower platform has this problem. > > I could explain the scheduling algorithm to you. (Much of the code is > just error checking.) Would that help you? soho: about maintenance of periodic schedule list, 1. like we can see some code get index from h/w by ehci_readl(ehci, &ehci->regs->frame_index) % mod, how about the purpose of % mod after get index from h/w 2. like stream->next_uframe is use by driver (software). Do you have flow chart to explan how to link urb to h/w periodic list and remove it from h/w? > > Alan Stern > > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
