On Mon, 23 Nov 2015, Patrick Shirkey wrote: > >> Is there a method to determine if the system has multiple or single > >> controllers available? > > > > lspci will tell you. > > > >> Do you or anyone else here have a link to the sysfs command to unbind > >> the > >> controller? > > > > If you provide the output from "lspci", I will tell you what command to > > use. > > > > Here's the USB info from lspci. > > # lspci > > 00:14.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset > Family USB xHCI (rev 05) > 00:16.0 Communication controller: Intel Corporation 8 Series/C220 Series > Chipset Family MEI Controller #1 (rev 04) > 00:1a.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset > Family USB EHCI #2 (rev 05) > 00:1d.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset > Family USB EHCI #1 (rev 05) The first one is the xHCI controller and the last two are EHCI controllers. The command to unbind the xhci-hcd driver from the controller is this (as root): echo 0000:00:14.0 >/sys/bus/pci/drivers/xhci_hcd/unbind To rebind the driver back to the controller, you do: echo 0000:00:14.0 >/sys/bus/pci/drivers/xhci_hcd/bind > >> In regards to the last item can you provide some more details on why the > >> software switch is only set if the kernel module is enable/disabled? > >> > >> I assume it has something to do with compiler flags and run time > >> efficiency? > > > > No, it's simpler than that. If the kernel is built without support for > > xHCI, it would be foolish to connect devices to the xHCI controller -- > > then the system wouldn't be able to communicate with them! > > > > Conversely, if the kernel does have support for xHCI, we assume that > > the user will prefer xHCI over EHCI if the motherboard has xHCI. > > Therefore the switch does get set to connect devices to the xHCI > > controller. > > > > Obviously the solution above should suffice for my purposes but out of > interest is it viable to make the switch accessible to run time > configuration? I don't know. Mathias (the Linux xHCI maintainer) is the right person to ask. 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
