Sea Islands is the forthcoming Radeon HD 8000 series built atop the GCN 2.0 architecture. While to be delivered in H2'2013, AMD has finally managed to deliver open-source support prior to the driver's launch. The HD 8000 builds upon the HD 7000 "Southern Islands" GCN generation so it's less of a hurdle to jump.
With the kernel bits set to be merged for Linux 3.11, Alex has gone ahead and updated the libdrm, xf86-video-ati DDX, and Mesa with the initial Sea Islands support on the user-space side.
Sea Islands is also known as "CIK" and less than an hour ago came the initial Sea Islands chipset support by extending the RadeonSI Gallium3D driver. With this initial Sea Islands support is handling for the Bonaire, Kaveri, and Kabini chip types. Following commits made other RadeonSI user-space driver changes, register updates, disabling of 2D tiling for now due to problems with Sewa Islands, and other alterations in the initial HD 8000 series bring-up.
On the xf86-video-ati driver side, with all of the mode-setting and fun stuff happening within the DRM driver in kernel-space, for the X.Org code it's mostly about adding in new PCI IDs. The initial Bonaire PCI Ids include 0x6640, 0x6641, 0x6649, 0x6650, 0x6651, 0x6658, 0x665C, and 0x665D. The current AMD Kabini PCI IDs include 0x9830, 0x9831, 0x9832, 0x9833, 0x9834, 0x9835, 0x9836, 0x9837, 0x9388, 0x9839, 0x983A, 0x983B, 0x983C, 0x983D, 0x983E, and 0x983F.
Look for the AMD Radeon HD 8000 "Sea Islands" graphics cards to appear on the market within a few months time. The AMD Catalyst driver should have launch-day coverage of the new GPUs while the main versions to look out for on the open-source side will be the Linux 3.11 kernel or later and Mesa 9.2 or later.