xHCI closest to OHCI or UHCI?

[USBVIDPID]

Hello, when using the xHCI in FS mode, does the xHCI act more like an OHCI or UHCI host controller?

Thanks, James

[Jan Axelson]

I don't know the answer. Why is it important? All three comply with the USB spec.

[USBVIDPID]

Jan, it is important, because I have an old device that I have support that only runs on UHCI and not OHCI.  The device is a NetChip NET2890.

I am looking for PCIe USB host function that will do the job of FS UHCI.

James

[Jan Axelson]

You're looking for hardware that the device will work on? Have you tried it with xHCI? Or an external hub?

[USBVIDPID]

Jan, I have tried it with neither the xHCI or an external hub.  I have located a USB 3.0 host on a motherboard and I will try this system shortly.  I have to assume that this USB 3.0 host is xHCI compliant.

Thanks

[Jan Axelson]

An external hub is also easy to try.

[USBVIDPID]

NetChip Net2890 does not work on Etron xHCI USB 3.0 host controller.  It shows as an unknown device in device manager on Win XP.  I tried uninstalling it and I tried to force install the driver that I have for the Net2890 function and it did not work.  Win XP OS "says" driver is not for this device, but the driver works fine when the device is connected to an EHCI with UHCI as the FS host.  USBView.exe does not show the device connected at all even though device manager shows the unknown device.  I know for sure that the unknown device is this Net2890, because I can plug and unplug the device and see the "unknown device" appear and disappear in device manager.  I did not do an USB trace of this, but I have done USB traces of the other attachments, and I see no response to the GetDescriptor Requests and I see no Firmware Interrupts either from the Net2890 chip.

The only thing that I have found that works for this device is the UHCI that is in the VIA Vectro VT6210L - 2-port USB 2.0 Host Controller.

I also know that the USB 2.0 compliant hubs do not work either when connected to a EHCI host controller.  For example if I hook a USB 2.0 hub to this VIA Vector VT6210L, and then the NetChip Net2890, it will not work.

Thanks, James

[Jan Axelson]

Do you need to fix the device so it works on all host controllers? Or is the Via host controller enough to enable you to support the device?

[USBVIDPID]

Jan, We have product in the field, with the NET2890 install so it would cost less to use a VIA Vector VT6210L on an add-in card in hardware that doesn't have a UHCI functional USB Host interface.  Our older PCs work fine it is the newer hardware that does not.

James

[Barry Twycross]

XHCI doesn't work like any other controller. There were one of two devices which seemed to have problems with XHCI, I can't remember the details.

[USBVIDPID]

I think even the UHCI if Bandwidth Reclamation is enabled will send the data too fast for the NetChip NET2890.  I understand that versions of Linux do this, i.e. turn on Bandwidth Reclamation.  The only way then in these Linux systems is to turn off Bandwidth Reclamation to make the NetChip NET2890 work.

James