Last week Intel released the graphics programming documentation and register specifications for Ivy Bridge processors. This Ivy Bridge graphics core programming documentation spans 17 files spread across three volumes and 2,468 pages of technical details concerning their latest-generation graphics, reported Phoronix. The complete public documentation can be downloaded for free here.
“While Intel has a large team of developers within their Open-Source Technology Center working on their open-source Linux graphics driver, they continue to produce very detailed programming documentation for the public. These documents cover the key registers for their hardware and other information to benefit anyone wishing to get into low-level graphics driver programming or just wanting to better understand how Intel's latest graphics core works,” the report reads.
Intel has put out documentation on their graphics chips for several generations now. The Ivy Bridge processors have been available since April, and the open-source Linux code for the graphics driver has been available for more than a year, but they finally received permission to do the public drop of their programming documentation.
This Intel HD Graphics Open Source Programmer’s Reference Manual (PRM) describes the architectural behaviour and programming environment of the Ivy Bridge chipset family. The Graphics Controller (GC) contains an extensive set of registers and instructions for configuration, 2D, 3D, and video systems. The PRM describes the register, instruction, and memory interfaces, and the device behaviours as controlled and observed through those interfaces. The PRM also describes the registers and instructions, and provides detailed bit/field descriptions.
This documentation is divided into four volumes containing 17 PDF files. The first volume covers the graphics core, MMIO registers and programming environment, memory interface, commands for the render engine, blitter engine, the video codec engine command streamer and the GT interface register. The second volume covers 3D media pipeline, L3 cache/URB, media and general purpose pipeline and the multi-format transcoder. Volume 3 covers VGA and Extended VGA registers, PCI registers, and the north/south display engines, while the fourth volume covers subsystem cores - message gateway, URB, video motion estimation, and execution unit ISA.
“It's nice to see that even the Ivy Bridge execution unit is covered with this documentation for doing general purpose computing (GPGPU). At this time that's one of the missing features of the open-source Intel Linux driver,” the report added.
The Ivy Bridge represents a ‘Tick’ in Intel’s ‘Tick-Tock’ cycle of upgrades. The ‘Tick’ stage is merely a die shrink of their current architecture - in this case Sandy Bridge. Ivy Bridge is still based on the same microarchitecture as Sandy Bridge, with the only difference being it’s based on the 22nm fabrication process instead of 32nm. Of course, it’s not just a die shrink as Intel has added some new features as well to Ivy Bridge. Ivy Bridge re-uses the LGA 1155 from the Sandy Bridge, making it backwards compatible with Sandy Bridge. Additionally it supports Intel’s Rapid Storage 11 technology, native USB 3.0 support, up to three display support via the integrated graphics card, PCIe Gen 3, UEFI BIOS and DirectX 11 support.