On Mon, 23 Nov 2015, Patrick Shirkey wrote: > Thanks Alan, > > FYI, running these commands exhibits some interesting behavior on my machine. > > Unbinding disables all external ports. > > [7946053.417529] xhci_hcd 0000:00:14.0: remove, state 4 > [7946053.417537] usb usb4: USB disconnect, device number 1 > [7946053.418082] xhci_hcd 0000:00:14.0: USB bus 4 deregistered > [7946053.418091] xhci_hcd 0000:00:14.0: remove, state 1 > [7946053.418110] usb usb3: USB disconnect, device number 1 > [7946053.418112] usb 3-1: USB disconnect, device number 2 > [7946053.469171] usb 3-2: USB disconnect, device number 3 > [7946053.469643] sd 196:0:0:0: [sdf] Synchronizing SCSI cache > [7946053.469692] sd 196:0:0:0: [sdf] Synchronize Cache(10) failed: Result: > hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK > [7946053.503557] usb 3-3: USB disconnect, device number 4 > [7946053.531384] usb 3-4: USB disconnect, device number 5 > [7946053.531389] usb 3-4.1: USB disconnect, device number 7 > [7946053.531392] usb 3-4.1.1: USB disconnect, device number 10 > [7946053.531394] usb 3-4.1.1.5: USB disconnect, device number 14 > [7946053.532460] usb 3-4.2: USB disconnect, device number 9 > [7946053.532465] usb 3-4.2.1: USB disconnect, device number 12 > [7946053.532468] usb 3-4.2.1.5: USB disconnect, device number 17 > [7946053.533093] usb 3-4.2.2: USB disconnect, device number 15 > [7946053.533402] usb 3-4.2.5: USB disconnect, device number 19 > [7946053.535962] usb 3-4.3: USB disconnect, device number 11 > [7946053.535967] usb 3-4.3.1: USB disconnect, device number 16 > [7946053.535970] usb 3-4.3.1.1: USB disconnect, device number 21 > [7946053.536309] usb 3-4.3.1.3: USB disconnect, device number 24 > [7946053.536559] usb 3-4.3.1.4: USB disconnect, device number 27 > [7946053.536659] usb 3-4.3.1.5: USB disconnect, device number 30 > [7946053.537003] usb 3-4.3.7: USB disconnect, device number 20 > [7946053.539933] usb 3-4.4: USB disconnect, device number 13 > [7946053.539938] usb 3-4.4.1: USB disconnect, device number 18 > [7946053.539941] usb 3-4.4.1.1: USB disconnect, device number 23 > [7946053.539944] usb 3-4.4.1.1.5: USB disconnect, device number 28 > [7946053.542235] usb 3-4.4.1.5: USB disconnect, device number 25 > [7946053.542711] usb 3-4.4.1.7: USB disconnect, device number 29 > [7946053.543885] usb 3-4.4.2: USB disconnect, device number 22 > [7946053.543890] usb 3-4.4.2.1: USB disconnect, device number 26 > [7946053.546309] usb 3-5: USB disconnect, device number 6 > [7946053.546968] usb 3-7: USB disconnect, device number 8 > [7946053.613004] xhci_hcd 0000:00:14.0: USB bus 3 deregistered > > > > I see the following with lsusb after unbinding: > > # lsusb > Bus 002 Device 002: ID 8087:8000 Intel Corp. > Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 001 Device 002: ID 8087:8008 Intel Corp. > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > - Un/plugging devices appears to have no effect: > > - Binding enables all external ports again without un/plugging. > > Does this behavior suggest that even if I disable xHCI at BIOS level I may > not be able to use the eHCI controllers stand alone on this machine or is > there something else I can tweak at the system level? I can't tell. The easiest way to find out is to try it and see what happens. As far as I can see there's nothing left in the kernel for you to tweak, aside perhaps from building a kernel with no xHCI support at all. 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
