On Mon, 20 Feb 2012, Wizard wrote: > >> Yes the ohci-hcd driver know this, while the usb device, such as keyboard > >> mouse, use this address format? > > > > No, that format is used only by the OHCI hardware. �USB devices use a > > similar but different format, described in the USB-2.0 spec (see Figure > > 8-5). > > > You mean the Figure 8-5, Token Format. Right. > PID, ADDR, ENDP, CRC5 > 8 7 4 5 > > Hmm... this just looks like the fields in the ED. > ADDR <-> FA > ENDP <-> EN As I said, it is similar but not the same. For example, in the ED the low-order bit of EN is adjacent to the high-order bit of FA, but in the Token packet it is the other way around. Also, the ED has no CRC field. > And I think the Token Packet is sent in the hardware? Yes. > This is seen by the device driver? No; it is seen only by the hardware. 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
