FreeVGA: architecture independent video graphics initialization for LinuxBIOS

LinuxBIOS is fast becoming a widely accepted alternative to the traditional PC BIOS for cluster computing applications. However, in the process it is gaining attention from developers of Internet appliance, desktop and visualization applications, who also wish to take advantage of the features provided by LinuxBIOS, such as minimizing user interaction, increasing system reliability, and faster boot times. Unlike cluster computing, these applications tend to rely heavily on graphical user interfaces, so it is important that the VGA hardware is correctly initialized early in the boot process in additional to the hardware initialization currently performed by LinuxBIOS. Unfortunately, the open-source nature of LinuxBIOS means that many graphic card vendors are reluctant to expose code relating to the initialization of their hardware in the fear that this might allow competitors access to proprietary chipset information. As a consequence, in many cases the only way to initialize the VGA hardware is to use the vendor provided, proprietary, VGA BIOS. To achieve this it is necessary to provide a compatibility layer that operates between the VGA BIOS and LinuxBIOS in order to simulate the environment that the VGA BIOS assumes is available. In this paper we present our preliminary results on FreeVGA, an x86 emulator based on x86emu that can be used as such a compatibility layer. We will show how we have successfully used FreeVGA to initialize VGA cards from both ATI and Nvidia on a Tyan S2885 platform.