On Wed, 12 Mar 2014, Peter Stuge wrote: > David Mosberger wrote: > > >> I couldn't figure out how to force UHCI onto an EHCI chip > > > > > > I suggested removing the ehci_hcd driver. Did that work? > > > > Nope. UHCI was loaded but it didn't recognize any UHCI-compatible > > chips so I was left without any USB devices (not even keyboard). > > Hmmm. Did you unload ehci_hcd after it had been loaded once, or boot > a kernel which didn't include ehci_hcd in the first place? You might > need to do the latter. > > lspci should show the UHCI companion controllers on the PCI bus. > (OHCI is also allowed by the EHCI spec, so maybe this is it? Check > lspci. Then include ohci_hcd instead.) Peter, David's computer doesn't have any UHCI controllers. Everything is handled by EHCI, through a hub on the motherboard. This is the standard design for current Intel systems. > > >> but I did find I had some old IOGEAR USB 1.1 "extenders" (USB-over-CAT5 > > >> cable) and with those, the device does switch into full-speed mode on my > > >> computer: > > > > > > It might not be comparable. > > > > I just need proof that the devices can be operated properly with > > full-speed transactions only. As long as it does that, I should > > be fine. > > I'm afraid that it will be more complicated than that. I would make > sure to try many different full-speed host controllers. > > Connecting to the root port of an EHCI controller connects directly > to the companion controller for that port, when no ehci_hcd was > present in the system since boot. David's computer has no companion controller. 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
