Enabling Vc4Graphics and v4l2 on RPI for Thunder builds

• Introduction
• Current RDK CMF Structure 
• Environment Setup
  • Set-up Considerations
  • User Access Considerations
  • Accessing the System
  • System Work Flow
  • Exiting the System
• Executing System
• Troubleshooting
  • Error Messages
  • Special Considerations

This Page is under Development

Introduction

      The Broadcom VideoCore 4 (present in the Raspberry Pi) contains a OpenGL ES 2.0-compatible 3D engine called V3D, and a highly configurable display output pipeline that supports HDMI, DSI, DPI, and Composite TV output. The 3D engine also has an interface for submitting arbitrary compute shader-style jobs using the same shader processor as is used for vertex and fragment shaders in GLES 2.0. Closed source graphics stack runs on VC4 GPU and talks to V3D and display component. Vc4 uses mesa instead of userland for graphics. Mesa is an open source software implementation of OpenGl, Vulkan and other graphics API specification. Mesa translates these specifications to vendor specific graphics hardware drivers.

Current RDK CMF RPI Structure 

  Current RPI structure uses userland to send OpenGL commands to GPU/VPU through VCHIQ.  One of the major drawback of current approach is OpenMax IL for 64 bit is not officially supported. VCHIQ also needs changes for supporting 64 bit architecture.

 New  Structure

Environment Setup  

The build procedure is as follows:

•  repo init -u https://code.rdkcentral.com/r/manifests -m rdkv-asp-nosrc.xml -b thunder-next
•  repo sync -j4 --no-clone-bundle
•  source meta-cmf-raspberrypi/setup-environment (select option raspberrypi-rdk-hybrid-thunder.conf)
•  bitbake rdk-generic-hybrid-thunder-image

•  Flashing the image

     Image is flashed to SD card before inserting to RPI board.   

  Command to flash the image

      Generated image has to be flashed to an SD card using this command in local PC:

  $ sudo dd if=<path to ImageName.rpi-sdimg> of=<path to SD card space> bs=4M

The SD card is then inserted to the Raspberry Pi board and booted to check for containers created. The Raspberry Pi board is connected to the PC via a USB to serial converter and the logs can be checked in console or can be connected via HDMI cable to a TV and logs will be shown in the terminal

• System Work Flow

References

•  http://heim.ifi.uio.no/~knuto/kernel/4.14/gpu/vc4.html?highlight=vc4
•  https://en.wikipedia.org/wiki/Free_and_open-source_graphics_device_driver