Reverse Engineering PowerVR Is Now A High Priority
Following a proposal last month of reverse-engineering the PowerVR SGX GPU to create a "free software OpenGL library", the Free Software Foundation has agreed this is a high priority project. "PowerVR is a popular 3D graphics engine found in phones, netbooks, and laptops, for which we currently have no free software driver capable of doing 3D graphics acceleration."
The Wiki page for this project outlines the goals as being to create a Gallium3D PowerVR driver called G3D-SGX, port the OpenGL 3.0 Mesa library to G3D-SGX (but no complete OpenGL 3.0 implementation is yet available for Mesa...), investigate compiling through LLVM (the Low-Level Virtual Machine) to take advantage of the multi-core SoC with the ARM Cortex A9 and other CPUs along with the vertex processing units and other co-processors on many of these SoCs. Their last, lower-priority goal is to create a DirectX acceleration for use by Wine. Phoronix readers will already know that there is a Direct3D 10/11 state tracker for Gallium3D.
The G3D-SGX goal of using LLVM to take better advantage of the SoCs where the PowerVR SGX is often deployed is quite interesting. Hopefully many of those goals will align and fit into the grand scheme of other plans with the LLVM IR of LunarGLASS and other projects to take advantage of this compiler infrastructure within Mesa and Gallium3D. Taking the Gallium3D route also means in-kernel memory management and very likely we'll see kernel mode-setting too, assuming this project materializes.
Before worrying about nifty features, the project needs to reverse-engineer the SGX and actually get an open-source driver working. Right now only the USSE opcodes and assembly have been decoded. The SGX reverse-engineering is being done in part by modifying PowerVR's kernel shim, which is open-source as it's what compiles against the kernel, to dump the information being passed to the driver.
Having an open-source PowerVR driver for Linux would be a huge win. Right now one of the only open-source mobile graphics drivers is the reverse-engineered Samsung GLES driver while some vendors have tried putting out open-source kernel drivers while leaving the user-space library closed-up. The embedded Linux GPU situation is a huge mess as it stands right now, but last month we reported that there may be an open-source PowerVR driver in Q3-2011, but now it seems that the free software community will not wait until then to see such open hardware support.
The PowerVR SGX from Imagination Technologies is what powers Intel's Poulsbo and Moorestown graphics and SoCs using its IP are found in the Apple A4 (iPhone 4 / iPad), Texas Instruments OMAP 3/4 with the Nokia N900, Motorola Droid, Archos 70, Samsung Hummingbird SoC with the Galaxy S / Galaxy Tab, and many other mobile devices.
Other high priority free software projects by the FSF include the development of the Gnash Flash player, the Coreboot open-source BIOS project, a free software replacement to Skype, free software video editing software, a free Google Earth replacement, reversible debugging in GDB, and free software drivers for network routers.