By admin 
This week’s batch of AMDGPU Display Core “DC” updates arrived heavy with 70 new patches for improving that open-source display support for Radeon graphics on the Linux desktop.
For those wanting to use the modern Apple Studio Display with AMD Radeon graphics on Linux, this week’s AMDGPU DC patches contain an important fix. The Apple Studio Display is a beautiful 27-inch 5K Retina display, but its DisplayPort handling by the AMDGPU DC driver is currently insufficient. The display exposes two Single-Stream Transport (SST) DisplayPort links for a 2×1 tiled panel. The first link has the proper 5120×2880 mode with Display Stream Compression. The new AMDGPU DC patch is now hiding/disconnecting that second link for the Apple Studio Display to avoid that from being exposed to user-space.
On current Linux kernels with the AMDGPU driver, desktop compositors could end up trying to unnecessarily and confusingly drive both tiled streams independently rather than just that single 5K mode. Once these latest AMDGPU DC patches reach the mainline kernel, those wanting to use AMD Radeon graphics on Linux with the Apple Studio Display will find just the single 5K stream on the primary link only.
Among the AMDGPU DC patches is also increasing the HDMI AV mute wait from 2 to 3 frames due to some HDMI sinks needing more time otherwise there could be garbled display outputs when resuming from suspend.
The AMDGPU DC patches also bring SPL UPSP upsampling and YUV422 scaling support, improved KUnit test coverage, and other enhancements.
See this mailing list patch series for all the latest AMDGPU DC changes. Given the current timing, these DC patches are still likely to make it for the upcoming Linux v7.3 cycle.