On 13.10.2019 3.33, Bernhard Gebetsberger wrote:
According to the xhci specification(chapter 4.6.8.1) soft retry shouldn't be used if the slot id is higher than 0. Currently some usb devices break on some systems because soft retry is being used when there is a transaction error, without checking the slot id.
That is not correct Specs say that soft retry should not be used if we are dealing with a FS/LS device behind a HS hub, this can be checked from the "TT Hub Slot ID" field in the slot context, which we do. In xhci all devices have a slot id, so this change would prevent soft retry almost completely. Specs 4.6.8.1: "Soft Retry attempts shall not be performed if the device is behind a TT in a HS Hub (i.e. TT Hub Slot ID > ‘0’)." -Mathias
