AMD Will Soon Support FreeSync on Linux With their New AMDGPU DAL Driver
FreeSync is AMD’s variable refresh rate graphics feature that is designed to eliminate choppy gameplay and broken frames with fluid, artifact-free performance. The technology, which is available in select AMD GPUs, works by resolving the communication issues between processor and monitor, reducing image tearing and stuttering effects for effortlessly smooth gameplay.
Since its launch back in March of 2015, more than 40 FreeSync-compatible displays have hit the market, with many more coming this year thanks to AMD’s technical collaboration with Acer, LG, and Samsung. Despite the growing adoption, the US based chipmaker has yet to offer support for the FreeSync tech via their open or closed-source Linux drivers. But now, it looks like the wait is almost over for AMD Linux customers.
AMD is apparently working towards FreeSync display parity with their proprietary AMDGPU DAL driver. The news comes from Harry Wentland, Senior Software Engineer at AMD, who described the architecture in a detailed message, with main part as follows:
The goal with DAL is to provide a unified, full featured display stack to service all of our Linux offerings. This driver will have to support our full feature set beyond what’s supported by amdgpu, e.g.
– synchronzied timings across different displays
– solid support of 6 displays in any configuration (HDMI, DVI, DP, DP MST, etc)
– solid support of 4k at 60 timings on APUs
– power features, such as
– clock-accurate bandwidth formulas
– improved interaction with powerplay to maximize power savings
– Improved audio and other infoframe related features
– Improved stability with powerplay since display hw is involved in the SMC hw interactions and improper programming sequences can lead to GPU hangs, etc.
The current amdgpu display stack grew somewhat organically and as such is not well suited to handling all of the hardware dependencies involved especially in areas like audio. The drm abstractions used by the old code map less and less well to new hw pipelines. Atomic helps, but if we are going to convert, it seemed like a good time to start fresh.
In addition, Wentland shed light on other technical stuff including Display Core (DC), how it doesn’t always map well to the DRM interfaces, and usage of the DAL internal abstractions to match the abstractions used by AMD drivers for other OSes. You can read the whole message HERE.