AMD Launches Pitcairn GPUs, Open-Source Not There

Yesterday AMD officially launched the Radeon HD 7800 "Pitcairn" series as the latest hardware in their Southern Islands family to reside between the Radeon HD 7700 series and their flagship Radeon HD 7900 cards. Unfortunately, the open-source support for these latest AMD GPUs remains unavailable.

These Pitcairn 28nm GPUs currently make-up the AMD Radeon HD 7850 and Radeon HD 7870. The Radeon HD 7850 packs 1024 stream processors, an 860MHz reference clock, 2GB of 4.8GHz effective GDDR5 memory clock on a 256-bit bus, and will be burning up to 150 Watts. The Radeon HD 7870 meanwhile has 1280 stream processors, 1GHz core clock, 2GB of 4.8GHz GDDR5 on a 256-bit bus, and consumes up to 190 Watts. Both of these cards are based upon their "GCN" architecture. The HD 7850 will start off selling for about $250 USD while the HD 7870 is at $350 USD. (There's reviews on OpenBenchmarking.org.)

Seeing as AMD has had to release hot-fix drivers in order to support the latest Radeon HD 7000 series at launch, chances are that any immediate customers of the Radeon HD 7850/7870 hardware will need to wait a few days until there's a new hot-fix release or AMD puts out a supported monthly build. With some of the older generations, the Linux support has been there at-launch with that month's driver (or even the previous month's version), but AMD isn't hitting that yet for Southern Islands.

Like the other Southern Islands launches, but contrary to previous Radeon generations, AMD hasn't sent over any hardware samples to Phoronix so there's been effectively no in-depth Linux hardware coverage of the Radeon HD 7000 series. I was told back at CES in January that some hardware should be on the way as they expand the Southern Islands family, but with the HD 7800 series launch they've now rounded out the family and alas there's nothing.

The lack of any Linux coverage of the HD 7000 series has made me extremely curious about the state of the Radeon HD 7000 series hardware under Linux with Catalyst. There's been some complaints about the state of the Windows Catalyst driver for the new GCN hardware, so what's it like under Linux? It's quite important since right now there's no open-source support for the HD 7000 series, so you're bound to using the Catalyst blob... or a useless VESA driver.

I ended up buying a Radeon HD 7950 this past week (though the lower-cost HD 7850/7870 would have been better...) to see what the Linux support is like for Catalyst.

The purchased hardware is finally expected to arrive today, so you can finally expect some extensive GCN Catalyst Linux benchmarks in the coming days from the $470 graphics card.

After seeing how Catalyst is running for the AMD Radeon HD 7950, it will be a waiting game to see when the open-source support arrives. AMD will hopefully have their updated Radeon DRM kernel driver to publish in the next two weeks. We may just be days away from the Linux 3.3 kernel, which would then open up the Linux 3.4 kernel merge window. Seeing as the GCN hardware has been available for months, hopefully we will finally see the open-source kernel support land in the 3.4 kernel. If not, it will be another disappointment.

On the user-space side, a new Gallium3D driver is needed. This Radeon HD 7000 series Gallium3D driver is based upon a stripped-down "R600g", but at least that can land in Mesa Git master at any-time for Mesa 8.1 since we're still months away from its next release. Any xf86-video-ati DDX changes can also land at any point, but the main question will be when the Radeon DRM/KMS support is there.