Manual Pages — EHCI

ehci – USB Enhanced Host Controller driver

EHCI controllers are peculiar in that they can only handle the USB 2.0 protocol. This means that they normally have one or more companion controllers (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 different USB buses.

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).

hw.usb.ehci.debug
	Debug output level, where 0 is debugging disabled and larger values increase debug message verbosity. Default is 0.

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