On Sat, 28 Jun 2014, Grant wrote: > >> I would > >> have thought USB2 would still work but I think I tried disabling > >> xhci_hcd and enabling ehci_hcd/ohci_hcd on my USB3 laptop and it > >> didn't work. > > > > What exactly do you mean when you say it didn't work? Does your USB-3 > > laptop contain any EHCI or OHCI controllers? > > > From memory, my Dell XPS 13 laptop wasn't able to detect any devices > without xhci enabled. It looks like it does have ehci controllers so > maybe something else was going on: > > 00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset > Family USB xHCI Host Controller (rev 04) > 00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset > Family USB Enhanced Host Controller #2 (rev 04) > 00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset > Family USB Enhanced Host Controller #1 (rev 04) Maybe the ports aren't connected to the EHCI controllers. Or maybe they are connected to both EHCI and xHCI, and the BIOS determines which will be used -- check the BIOS settings. Or maybe the ports are connected to both and xhci-hcd automatically initializes the system so that only the connection to xHCI is used. Try blacklisting the xhci-hcd driver. 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
