I'm running Fedora 19 with a 7870. I tried running the Unigine "Valley" benchmark, but it spits out gibberish, which I believe indicates it needs a higher version of OpenGL.
On my system, glxinfo shows:
OpenGL vendor string: X.Org OpenGL renderer string: Gallium 0.4 on AMD PITCAIRN OpenGL version string: 2.1 Mesa 9.2.0 OpenGL shading language version string: 1.30 OpenGL extensions:
My prior experience with Linux tells me that there's a simple 22 step process to fix this, and it involves recompiling the kernel.
If your problem is indeed that it needs higher than OpenGL 3.3 (the highest version supported by the open source Radeon driver), you should need only to install the proprietary driver from AMD's website.
OK. If you're verifying this information somewhere, mind telling me where you're looking? I'd like to learn how to self-diagnose, and want a good source of information for linux internals.
If you're simply doing some magic on your own system, never mind -- I'll just have to learn it myself.
I may install Catalyst, but the last time I did, it hosed the Intel graphics drivers (I have integrated graphics on my system as well as the 7870). I strenuously object when installing an rpm can cause X not to start...
Well, I figured out that Fedora 19's version of Mesa was limited to OpenGL 2.1 on a 7870 because I happened to also be running Fedora 19 on a system with a 7870. I ran glxinfo just like you did, to verify that there wasn't some configuration issue, or you weren't just behind on updates or missing some detail in the giant output soup glxinfo gives you.
I know things about OpenGL support by various drivers and such because I dabble in OpenGL programming. Catalyst on Linux would support OpenGL 4.3 because it's generally kept even with Windows Catalyst, or at least it was, for the two years or so that I used it.
Fixing things usually just takes experience. And Google. Mostly Google. If you want to keep up to date, Phoronix is a good place, at least for video cards and such. They do benchmarks comparing new versions of Mesa, drivers, distros, etc.
Which driver you use depends on what you'll be doing. If you want to play the more demanding 3D games that have been coming to Linux recently, you'll need Catalyst. But,Catalyst pretty much sucks at everything else. Last I used it, even dragging windows around on the desktop was slow and choppy. 2D performance somehow isn't there.
The open source driver gives a very smooth desktop experience, and it's very stable. The 3D performance is passable (highly dependent on what you're doing), but (as I said earlier) OpenGL support is behind.
Fedora 19 stable is on mesa 9.2 with kernel 3.11.7. That means the very latest stable mesa version, with support for OpenGL 3.1. You could upgrade to Fedora 20, but if it's a production machine, I'd stick with Fedora 19 tbh, Fedora 20 has different glibc etc, you have to install Catalyst and Steam manually if you want it to work 100%. Catalyst works fine, and compiles on all kernels, since about 9 months, Catalyst has not been posing any problems at all in linux. On a 7870, Catalyst is still the better option than the RadeonSI, which is not as evolved at the R600 driver, and with the RadeonSI driver, you'll get artefacts in shadows and lighting effects in games, whereas with Catalyst, you won't. On older non-GCN cards, the Radeon open source driver is the better option, also because AMD is gradually stopping linux Catalyst legacy support for them, as soon as the open source Radeon driver performs better for a series than the Catalyst legacy, they just take support for that series out of Catalyst. That will eventually happen to the GCN-cards also, since AMD is focusing on the open source driver development, but it will take a couple of extra months, and linux kernel 3.14, which is expected Q2 2014. AMD will probably move to OpenSource-only drivers by kernel 4.0 because of the HCA functionality. Fedora 21 will be an OpenCL HCA release, the entire distro will be optimized for hybrid computing. That means that by summer 2014, Fedora 21 will accelerate everything that can use OpenCL on the system, and AMD card equipped systems will become much faster than non-AMD card equipped systems.
The only problem I've observed with the built-in Radeon driver on Fedora 19, are rendering errors with the Settings window(s). At this moment I don't know how to update to a more recent version.