> From: Alan Stern > > This may be a foolish question, but why is xhci-hcd using no-op TRBs in > the first place? Because it can't write in a link TRB because other parts of the code use link TRBs to detect the end of the ring. The problem is that it can't put a link TRB in the middle of a chain of data fragments unless it is at a 'suitable' offset from the start of the data TD. Given arbitrary input fragmentation this means that you can't put a link TRB in the middle of a TD. (The documented alignment might be as high as 16kB.) If the rest of the code used a 'ring end pointer' then a link TRB could be used instead. David -- 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
