On Mon, 26 Aug 2013, Sarah Sharp wrote: > I double checked with the Intel Windows devs, and they say that Arjan is > mistaken, and they'll get around 11 ms, just like we do. > > They say: > > "The EHCI driver stack applies the 10 ms starting at the point that it > sees C_PORT_SUSPEND asserted for the port. > > The inaccuracy in Windows 8 is generally no more than 1 system clock > period late, but it can be delayed by interrupt processing for other > devices. I would expect the additional average delay to be no more than > 1 ms." > > They didn't mention waiting for the PORT_RESUME bit to be cleared, like > the Linux EHCI driver does. Alan, would you like me to ask them about > that?
Yes, please. You might also ask them what they meant by "it sees C_PORT_SUSPEND asserted for the port", since there is no C_PORT_SUSPEND bit in the EHCI Port Status and Control registers. Were they talking about external hubs instead of the root hub? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
