Intel develops simpler alternative to ACPI for Linux
A few days ago, version 4.0 of the Advanced Configuration and Power Interface (ACPI) specification was released, weighing in at a hefty 727 pages. Lead by Intel, PC manufacturers as well as operating system, driver, BIOS, firmware and software developers have, for more than a decade, been working on this specification, which is designed to enhance the configuration management and power saving features of computer hardware. Despite this, there are still flaws in many implementations.
Intel is now developing the Simple Firmware Interface (SFI) especially for small and low spec devices like Mobile Internet Devices (MIDs) with Atom processors, and is particularly targeting the Linux operating system with this alternative. Intel developer Len Brown is responsible both for version 0.6 of the SFI specification, which has been released as a draft, and for a patch to make the forthcoming 2.6.32 Linux kernel SFI compliant. The first Intel product to offer SFI compliance is Moorestown, a platform comprising a Lincroft Atom SoC (System on Chip) with integrated memory controller and GPU core in combination with the single-chip Langwell chipset and the Evans Peak WiMAX module.
The specification states that SFI can be implemented in addition to, or as an alternative to ACPI, in the firmware – either within a classic BIOS, (U)EFI, or with alternative firmware like OpenFirmware. The SFI FAQ explains that SFI and ACPI can smoothly coexist side by side; Like ACPI, SFI even uses an Extended System Description Table (XSDT) to give the operating system access to the extended configuration features of PCI-X and PCI Express devices (Memory Mapped Configuration Space, MMConfig), whose addresses are written into the MCFG table by the ACPI BIOS.