We were sent the ASUS Radeon HD 4890 graphics card and given the RV790 press presentation slides (although they mostly target the Windows user, obviously) and then set free to explore this new ATI graphics processor. While the Windows Catalyst 9.3 driver does not support the Radeon HD 4890, the case was not clear for the Catalyst 9.3 driver for Linux. With the 9.3 Linux release having deviated from the normal release schedule in order to deliver OpenGL Composite support prior to the R300 through 500 support being dropped, we decided to check whether the RV790 was already supported in the driver released last month. When running the ASUS Radeon HD 4890 1GB graphics card on an Ubuntu system with Catalyst 9.3, sure enough, it worked. While OpenGL acceleration was there, an "unsupported hardware" watermark was present in the lower right corner.
Next we turned to the first press release driver, which was based upon a release candidate of the Catalyst 9.4 Linux driver that will be released later this month. In the Catalyst 9.4 Linux driver, the RV790 graphics card was properly detected and was not classified as unsupported hardware. For reference, the PCI product ID of this Radeon HD 4890 graphics card is 0x9460. We proceeded to run some initial tests of the Radeon HD 4890 using this early Catalyst 9.4 build. Everything went smooth up until we began running tests using the id Tech 4 game engine. The OpenGL acceleration was broken with a frame-rate between 0 and 1 FPS, which is certainly a problem considering most modern games that run on Linux use this engine -- Doom 3, Quake 4, Prey, and Enemy Territory: Quake Wars. All other games on Linux ran just fine -- Compiz also had no problems on the desktop, complete with the recently introduced OpenGL Composite support.
The next step for us was to try out an advanced press release driver, which was an early release candidate of the Catalyst 9.5 driver for Linux. Due to the branching of the different release streams and how AMD manages their Linux driver, this Catalyst 9.5 driver back went to reporting it as unsupported hardware. However, OpenGL acceleration and all features besides aticonfig (there is a check in place that does not allow aticonfig to function on unsupported hardware) were working, we used this driver for our most of our testing. Due to aticonfig not working with the RV790 in this private release, we had to revert back to the Catalyst 9.4 release candidate when it came time to using OverDrive for overclocking and looking at the cooling performance.
To sum it up, the Linux support in the Catalyst Linux driver is there even as of the Catalyst 9.3 release. The basic functionality is all in place, but there are a few bugs that are being ironed out over the next release or two. It would be nice to see smooth, reliable support as of Catalyst 9.4, but considering for the R500 and R600 product generations we had to wait many months before seeing any level of support at all on Linux, this is not that bad.