EHCI(4) Kernel Interfaces Manual EHCI(4) NAME ehci -- USB Enhanced Host Controller driver SYNOPSIS device ehci DESCRIPTION The ehci driver provides support for the USB Enhanced Host Controller In- terface, which is used by USB 2.0 controllers. EHCI controllers are peculiar in that they can only handle the USB 2.0 pro- tocol. This means that they normally have one or more companion con- trollers (i.e., ohci(4) or uhci(4)) handling USB 1.x devices. Consequently each USB connector is electrically connected to two USB controllers. The handling of this is totally automatic, but can be noticed since USB 1.x and USB 2.0 devices plugged in to the same connector appear to connect to dif- ferent USB busses. SEE ALSO xhci(4), ohci(4), uhci(4), usb(4) HISTORY The ehci device driver first appeared in FreeBSD 5.1. LOADER TUNABLES Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). hw.usb.ehci.lostintrbug This tunable enables the lost interrupt quirk. The default value is 0 (off). hw.usb.ehci.iaadbug This tunable enables the EHCI doorbell quirk. The default value is 0 (off). hw.usb.ehci.no_hs This tunable disables USB devices to attach like HIGH-speed ones and will force all attached devices to attach to the FULL- or LOW- speed companion controller. The default value is 0 (off). FreeBSD 9.0 February 24, 2011 EHCI(4)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | LOADER TUNABLES
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