GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
EHCI(4) FreeBSD Kernel Interfaces Manual EHCI(4)

ehci
USB Enhanced Host Controller driver

device ehci

The ehci driver provides support for the USB Enhanced Host Controller Interface, which is used by USB 2.0 controllers.
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.

When the kernel has been compiled with options USB_DEBUG, some tunables become available that affect the behavior of ehci. These 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).

The following variables are available as both sysctl(8) variables and loader(8) tunables:
hw.usb.ehci.debug
Debug output level, where 0 is debugging disabled and larger values increase debug message verbosity. Default is 0.

ohci(4), uhci(4), usb(4), xhci(4)

The ehci device driver first appeared in FreeBSD 5.1.
April 24, 2018 FreeBSD 12.0-RELEASE

Search for    or go to Top of page |  Section 4 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.