Hi Alan, When reading the code (at qh_urb_transaction) about zero-length packet for EHCI, would you please help me on below questions: - I have not found the zero-length qtd prepared for control read (eg, the transfer size is multiple of wMaxPacketSize), Am I missing something? - Why the IN transfer doesn't need to prepare zero-length qtd? In the 2.0 spec, it does not say it is only for OUT. Ch 5.7.3 & Ch 5.8.3 A bulk (interrupt) transfer is complete when the endpoint does one of the following: - Has transferred exactly the amount of data expected - Transfers a packet with a payload size less than wMaxPacketSize or transfers a zero-length packet Ch 5.6.4 An isochronous IN endpoint must return a zero-length packet whenever data is requested at a faster interval than the specified interval and data is not available. Thanks. -- Best Regards, Peter Chen -- 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
