On Mon, 19 Jan 2009, Julie Zhu wrote: > Hello, > > We are working with a host controller on a PowerPC embedded board. It is > an EHCI host controller. However, there are no UHCI/OHCI host > controllers on the board. Therefore, if a FS/LS device plugs onto the > board, Linux will try to hand the port to a companion controller, which > is not there, and this causes the EHCI host controller die (or maybe the > port is marked dead?), and unplug the device causes no "disconnect" > report. The host controller also does not respond to further plug in of > a HS device. In theory this should work okay. It's not clear why your host controller dies. It could be a bug in the hardware design. > I wonder whether there is a way to configure the kernel such that if a > FS/LS device plugged in (where the host controller will not enable the > port), Linux will tell the user that "FS/LS devices are not supported", > and do nothing. When the device disconnects, "disconnect" will be > reported, and further plug-ins of HS devices can continue on. There is no way to do this, for a good reason: Hosts that don't support FS/LS are in violation of the USB spec. > Thanks, Pandita, that makes sense. I changed the two function > registrations to NULL, and got following message if plug in a USB mouse: > > hub 1-0:1.0: Cannot enable port 1. Maybe the USB cable is bad? > hub 1-0:1.0: Cannot enable port 1. Maybe the USB cable is bad? > hub 1-0:1.0: Cannot enable port 1. Maybe the USB cable is bad? > hub 1-0:1.0: Cannot enable port 1. Maybe the USB cable is bad? > hub 1-0:1.0: unable to enumerate USB device on port 1 > > And the host controller is dead (not responsive) after this. Do you have CONFIG_USB_DEBUG enabled in your kernel? Have you tried using usbmon to see what happens when the mouse is plugged in? 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
