On Mon, Sep 28, 2015 at 03:24:04PM +0300, Mathias Nyman wrote: > Driver will tell the latency value to the host controller, when a exit > latency time is set the host will know that the link is power managed, and > host will start to schedule additional PING TP transfers to the device to > wake the link up to U0. the PING TP tranfers are sent Max-exit-latency > microeseconds before the actual transfer to make sure link is woken up in > time. It's possible that this impacts on the bandwidth. > > It's also very possible that the max exit latency is calculated wrong, or > that one of the other parameters set with the same "evaluate context" > command is wrong Just so that it doesn't get lost: I've reported issues with this specific device and LPM not too long ago. It's entirely possible that the device somehow is broken, although it works in Windows 7/8/10 and OS X, from what I know, and at least Windows 10 uses USB3 LPM. Perhaps figuring out what's wrong with the ping timeouts would also fix this issue? I'm afraid I don't have any fancy USB analyzer equipment to debug with, though. In any case, I'll reiterate my request to turn off LPM for a specific device, no matter whose fault these specific issues are. :-) /* Steinar */ -- Homepage: http://www.sesse.net/ -- 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
