Timur Kristóf of Valve’s Linux graphics team last year addressed remaining issues in the open-source AMDGPU kernel graphics driver so old AMD GCN 1.0 and GCN 1.1 GPUs could transition to using AMDGPU by default rather than the former “Radeon” kernel driver that is largely in maintenance mode for pre-GCN/RDNA GPUs. One caveat though was the GCN 1.1 APU support still having some limitations leading to Kaveri and friends not being able to use the modern AMDGPU DC “Display Core” code. But new patches from Timur take care of those limitations.
This week Timur Kristóf posted a set of 14 patches for enabling support for some external DP bridge encoders in the AMDGPU DC code. With that DP bridge encoder handling wired up to the AMDGPU Display Core, this should hit feature parity for AMD APUs in desktops and laptops based on GCN 1.1 for using the modern AMDGPU DC support rather than the legacy display code.
With these patches, AMDGPU DC can be enabled by default for Sea Islands (GCN 1.1) APUs. In turn compared to the old Radeon driver, moving these AMD APUs over to the AMDGPU Linux driver enables DP/HDMI audio support, DisplayPort Multi-Stream Transport (DP MST), Variable Rate Refresh (VRR), 10-bit color, some high dynamic range (HDR) features, atomic mode-setting and other functionality that hadn’t been in place for the old driver code.
“With that, we can now enable DC by default on CIK APUs too. DC brings proper support for DP/HDMI audio, DP MST, VRR, 10-bit colors, some HDR features, atomic modesetting, etc. without any loss of functionality.”
The patches are now out for review but given the timing are unlikely to be seen for the upcoming Linux 6.20~7.0 kernel merge window and thus presumably won’t be mainlined until the summer with the follow-on ~7.1 kernel cycle. In any event this is a pleasant win for those still using older AMD Kaveri / Kabini / Mullins APUs on Linux.
Special thanks to Timur on Valve’s Linux graphics team for continuing to enhance the older AMD GPU support with the open-source Linux driver. Granted, many 2026+ games will not be too playable with Kaveri class APUs although for general desktop use this is a nice improvement too for long-awaited DP/HDMI audio, limited HDR functionality, and other features.
