One of the few feature complaints left among AMD Linux customers using the open-source driver has been for those with older GPUs/IGPs where UVD isn't supported. The open-source code right now supports UVD 2.0 and later. The first-generation UVD hardware was the RV600 series (Radeon HD 3000 series), RS780, RS880, and RV790 graphics processors. The RS880 was popular back in the day and there's still many Radeon HD 3000 series GPUs out in the wild. For those unfamiliar with the various UVD versions, there's extensive information on AMD's Unified Video Decoder generations via Wikipedia.
Many Phoronix readers are often asking about this open-source UVD 1.0 support, and it's been brought up again on Tuesday within the forums, so as a reminder, the code has been written but is pending approval for release.
Christian König at AMD wrote on a public mailing list earlier this month, "The code for the first generation UVD blocks (RV6xx, RS780, RS880 and RV790) is already implemented and I'm only waiting for the OK to release it. The only problem is that I don't know if and when we are getting this OK for release. Maybe tomorrow, maybe never. It just doesn't has a high priority for the reviewer because we don't really sell that old hardware any more."
Aside from the open-source developers, AMD really doesn't care much about that enablement anymore since the hardware is many years old. Additionally, it seems the common bottleneck for open-source AMD developers is always on code/technical/legal review for getting out new code. It's also always problematic when dealing with video code, especially on early UVD revisions where digital rights management is tightly coupled with this video decode block.
For years before the initial open-source UVD drop, one of the publicly expressed reasons it was difficult to get clearance on pushing out the code was due to risk of comprising digital rights management on Radeon hardware for other platforms if it was publicly documented or there was open-source code. Pair that now with hardware that AMD launched about seven years ago, and it makes it a very low priority work item that may (sadly) never materialize.