FreeBSD cx88 Wiki

Welcome to the FreeBSD cx88 Wiki!

This is a wiki for info on the new "cx88" video capture driver for FreeBSD. This driver shares its name and some supported hardware with the Linux cx88 driver, but uses a very different architecture and does not reuse any of the Linux driver's code.


cx88 is a package that provides kernel drivers and a simple capture application for video/audio capture cards based on the Conexant CX2388x family of PCI bridge chips.

What's a CX2388x?

The Conexant CX2388x is a series of what I informally call "multimedia bridge" chips. A multimedia bridge chip is responsible for providing an interface between a host data bus (e.g. PCI, PCI-express, USB, etc.) and a "frontend" for receiving audio or video signals. Frontends typically consist of a series of highly specialized pieces of silicon, such as RF tuner chips or digital TV demodulator chips. The bridge chip must provide a bus (typically I2C) for controlling frontend devices and expose functions for controlling the transfer of audio/video data across the host bus. Depending on the application, the bridge chip may also expose specialized functions for controlling the reception and decoding of the A/V signals.

Multimedia bridge chips are typically sold to A/V capture card vendors, who integrate those chips with a frontend package of their choice. Therefore, it is often the case that two different capture cards made by completely different companies will utilize the same bridge chip and differ only in their frontend configuration.

Supported Chips

The CX2388x family contains several iterations. The cx88 kernel drivers currently generically recognize any capture card based on the CX23880/1/2/3 flavors, as well as the newer CX23885/7/8 PCI-express chips.

Supported Operating Systems

The cx88 driver supports FreeBSD version 8.3 and later. The driver is actively tested and maintained against the FreeBSD 9-STABLE and 10-CURRENT branches. Snapshots of the driver prior to 20071215 were built against FreeBSD 6.2, and versions prior to 1.4.6 also supported FreeBSD 7.x.

Supported Architectures

The cx88 driver is known to work on i386 and amd64. It is intended to be machine-independent and should thus work on other architectures supported by FreeBSD, but AFAIK it hasn't been used outside of i386/amd64. Again, please let me know if you encounter problems with the driver on another architecture and I'll work to resolve them.

Driver Overview





cx88 (last edited 2013-10-05 04:46:54 by jason)