It is rumored that the ATI/AMD RS880 will be based upon the RV620 ASIC and will provide 40 Stream processors and other features similar to the 790GX, but will run with a ramped up core clock speed. Besides VGA and DVI support, the RS880 is also expected to support both HDMI and DisplayPort standards. The 55nm RS880 will also be compatible with UVD2, but sadly that is not supported under Linux at this time. The second-generation AMD Unified Video Decoder will be supported under Linux through their proprietary Catalyst driver once XvBA (the X-Video Bitstream Acceleration API) is officially supported.
Road-maps for the ATI RS880 had originally put it for a Q2'09 release, but then it was reported this IGP got pushed back to a planned Q3'09 introduction. It's unknown where the release of this chipset now stands, but the RS880 is now supported by the two open-source ATI drivers -- xf86-video-ati and xf86-video-radeonhd.
In a Git commit last night to both the -ati and -radeonhd repositories, the RS880 PCI IDs were introduced. There are five PCI IDs in total where 0x9710, 0x9711, and 0x9714 are apparently for the Radeon HD desktop graphics while 0x9712 and 0x9713 will be for a mobile version of the RS880. Beyond adding in the PCI IDs and a RS880 family enumerator, there were only two small changes (altering two conditional statements dealing with the memory controller) for the support in the RadeonHD driver. Similar changes were also made to the xf86-video-ati driver. These patches, however, had not exposed the marketing names for these new RS880 products. The Linux driver commits were made last night by Alex Deucher, who is one of the key AMD employees that focuses on their open-source efforts.
Considering the RS880 is based upon the RV620 GPU, it is to not much surprise that these patches are small. Both drivers use AtomBIOS for mode-setting and a good deal of the work, which also makes support for bringing up new ASICs easier. While the X.Org DDX drivers now support the ATI RS880, we have yet to see any Mesa/DRM patches that append these PCI IDs. It has yet to be officially corroborated, but it's also anticipated that the RS880 is already supported by the proprietary Catalyst Linux driver.
The patch for the xf86-video-ati driver can be found here while the xf86-video-radeonhd driver gained its support here. With the ATI RS880 release not being imminent, it's wonderful to see the open-source support being added so soon. Generally with the open-source drivers, we first see the hardware released before the support arrives -- even when it's been as simple as adding in the PCI ID or two. Heck, on a few occassions we have been the ones to discover the support when receiving early review samples of hardware that hasn't yet been seen by developers. Hopefully going forward this will emerge as a trend from AMD of seeing new support added to their open-source stack prior to the hardware's official release.
Look for the RS880 arriving sometime this year.