On 22.01.21 at 16:22 Mathias Nyman wrote: > On 22.1.2021 15.17, Andreas Hartmann wrote: >> But anyway, there is from my point of view a basic problem with xhci_hcd, >> which just seems not to be completely backward compatible to existing USB 2 >> drivers (see https://marc.info/?l=linux-usb&m=161130327411612&w=2) if the >> device is plugged to an USB 3.x interface. > > This looks like a different issue, lets keep it in its own thread. > > The xHCI usb host controller handles both USB 2 and USB 3 speeds. > If the USB port is connected to a xHC controller then the xhci driver will > be used. If the port is connected to a EHCI then the ehci driever is used. > EHCI does not support USB3 speeds. > > It's very possible that something that worked behind a EHCI host has issues > when connected to a xHCI host. I would be very glad to get this sorted out. At the moment I absolutely don't know where exactly to try to prevent to trigger the "xhci_hcd 0000:05:00.3: WARN Wrong bounce buffer write length: 0 != 512" situation. Is it on the level where the bulk packages are created or even before? Thanks Andreas
