Intel® Atom™ Processor Early Camera Presentation in Linux*: Note
Document Scope This document discusses the ingredients and best-known methods (BKM) for achieving early camera presentation in a Linux*-based system on an Intel® Atom™ processor E6XX based platform. The document includes programming guide for customers to achieve the aforesaid feature by optimizing the following 3 areas:...r>• Platform firmware • Linux* kernel & subsystem • Graphic System & USB video capture (UVC)
The early camera presentation is particularly useful in automotive reverse parking guidance system as a visual aid and other applications. This document does not discuss BKMs for optimizing Linux* subsystems such as Xserver, Linux* Init process, user shell process and others.
General Assumptions This document assumes that the reader is familiar with: • Reference Boot Loader from Intel • Linux* Kernel • Video For Linux* 2 (V4L2) • Intel® Embedded Media and Graphics Drivers (Intel® EMGD) • USB Video Capture (UVC) Driver
Technical Assumptions • Feature development is based on the Intel® Atom™ processor E660 with Intel® Platform Controller Hub EG20T Development Kit customer reference board. • Feature development is based on the standard Linux*-based kernel package (at minimum Linux* kernel version 2.6) • Intel® EMGD provides handshake interfaces to render V4L2 inputs to the hardware Overlay plane. This includes mapping video frame memory from the V4L2 driver to EMGD video memory, turning on or off direct video display, and directly presenting the video frame. • For simplification, one YUV4:2:2 FOURCC format is supported: YUY2. • An external switch was connected to the GPIO port to simulate reverse gear engagement.