AMD has published a Catalyst graphics driver for Linux with complete OpenGL 4.4 support. AMD Catalyst 14.4 RC for Linux can be downloaded from this page.
I tested this Cat 14.4 RC with Linux Mint 13 (I tried it before on Mint 16 but Cat 14.4 messed up the X server!). Here is a screenshot of the control center with a Radeon HD 7770:
GLSL Hacker gave me the following OpenGL info:
GL_RENDERER: AMD Radeon HD 7700 Series GL_VENDOR: ATI Technologies Inc. GL_VERSION: 4.4.12874 Compatibility Profile Context 14.10 GL_SHADING_LANGUAGE_VERSION: 4.30 OpenGL extensions: 289
With a full OpenGL 4.4 support, GL_SHADING_LANGUAGE_VERSION should return 4.40 and not 4.30. The OpenGL 4.4 support is almost complete (all important OpenGL extensions are present) and I think that GL_SHADING_LANGUAGE_VERSION will return 4.40 in the final version.
Now that AMD has added the OpenGL 4.4 support, I’m going to improve the bindless texture support in GLSL Hacker.
The complete list of all 289 OpenGL extensions exposed by Catalyst 14.4 RC under Linux 64-bit for a Radeon HD 7770 is available HERE (the list shows 288 extensions because GL_ARB_compatibility is not listed).