UHCI EHCI OHCI Basic Concepts
UHCI (universal host controller interface): The hardware interface EHCI (Enhanced Host Controller Interface) of the USB 1.1 host controller used by Intel on its own chipsets. The enhanced host controller interface specification describes a universal serial bus ( USB) version 2.0 host controller register-level interface. This specification includes a description of the hardware/ software interface between system software and host controller hardware. The purpose of this specification is for hardware component designers, system integrators and device driver (software) development. OHCI (open host controller inferface): a host controller interface standard not only for usb. Mainly follow the csr (configuration space register) standard. It is the standard that other manufacturers follow when designing usb host controllers, such as via, nec, ali, including nvidia and so on. EHCI is a hardware design that meets the requirements of usb host controller (high speed) in the usb 2.0 specification.
The difference between UHCI and OHCI
In terms of hardware, in order for a usb device to work, in addition to the peripheral itself, there must be a usb host controller. Generally speaking, a computer can have a usb host controller, which can control many devices. All peripherals submit their requests to the usb host controller, and then let the usb host controller make unified scheduling.
Now there are two types of general USB bridge modules, UHCI and OHCI . When deciding which bridge module to insert, look at the /proc/pci file to decide. . Generally speaking, the plug-in module of UHCI type bridge is uhci or usb-uhci (depending on the kernel version); and for OHCI type bridge, its plug-in module is ohci or usb-ohci.
The "EHCI" driver is designed to provide support for chips implementing the new Hi-Speed USB 2.0 protocol. The "OHCI" driver is used to provide support for USB chips on non-PC systems (and on PC motherboards with SiS and ALi chipsets ). The "UHCI" driver is used to provide support for USB implementations on most other PC motherboards , including Intel and Via. Simply select the "?HCI" driver that corresponds to the type of USB support you wish to enable.