On Thu, 8 Mar 2012, Edwin Mercado wrote: > Alan, > > There's no way to clear the data toggle for control endpoint on the > Maxim 3420e device. This rules out the ability of the CPU to clear the > data toggle for Set_Interface and Set_Configuration. The expectation > is that the hardware handles these conditions. I need to confirm this > with Maxim. That sounds right. The data toggle works differently for control endpoints than for other sorts. The CPU should not need to clear the toggle for endpoint 0, but it does sometimes need to clear the toggle for bulk and interrupt endpoints. > It seems that the only condition the CPU clears the data toggle is > when the host issues a Clear_Feature (endpoint stall) request. For bulk and interrupt endpoints, the CPU has to clear the data toggle when the host issues a Set-Configuration or Set-Interface request (assuming your device supports Set-Interface; not all devices do). See section 9.1.1.5 in the USB-2.0 specification. 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
