Yesterday's article concerning OpenGL 3.0 support in Mesa looked at Intel's plans to have OpenGL 3.0 / GLSL 1.30 support in Mesa before the end of the calendar year. There's just two months left and it looks like it will be a close call whether the necessary OpenGL extensions and GL Shading Language support will land around the start of the new year, which would mean Mesa 7.12 would be released as Mesa 8.0.
The progress of OpenGL 3.0 support in Mesa can be tracked via the GL3 documentation in the Mesa tree or in much greater detail (along with specific time estimates) via this FreeDesktop.org Wiki page. There's still a fair amount of work left to accomplish before OpenGL 3.0 support is officially done and the developers can then focus upon the OpenGL 3.1/3.2/3.3 and 4.0/4.1 support, but it will be many months (not likely before 2013) that this open-source 3D library catches up to the latest Khronos specification -- unless a miracle were to happen.
For those curious about some of these longer-term goals with regards to missing functionality from these more recent versions of OpenGL, there is another Wiki page worth pointing out. The DRI missing functionality page describes in some details where the Mesa/DRI support is currently lagging behind. It's not in as much detail as Intel's Wiki work queue page for GL3, but it's better than the "GL3.txt" documentation in the Mesa tree.
For items since implemented, the various OpenGL extensions or other features show the GL version it's apart of and the Mesa version where the support was introduced. It shows the Mesa support level for core Mesa, the i965 driver, and for the R600 Gallium3D driver. There's also additional notes on some drivers. The items are broken down into features pertaining to texture formats, draw-call, render-target, shading language, GLX / EGL, and miscellaneous features.
This isn't a new page to the Wiki, but it's still actively maintained and worth mentioning since I don't believe I've explicitly mentioned it before in a Phoronix news post for those interested in the open-source 3D support state of drivers (just getting some articles in order while en route to Florida for the Ubuntu Developer Summit).
Outside of OpenGL-related functionality, for those wanting to see the state of other features in the open-source Linux graphics drivers, below are some other references. However, if you're a frequent participant to the Phoronix Forums discussions and stay up to date on the Phoronix articles, there isn't much new information.
Radeon Program: The Radeon graphics support driver for specific games/applications.
Radeon Feature: A feature matrix for the Radeon graphics driver that's classified by the ATI/AMD Radeon hardware family/generation.
Nouveau Feature Matrix: A feature matrix for the Nouveau driver for the supported NVIDIA GeForce/Quadro graphics cards.