The Asahi Linux project celebrates five years of progress by achieving long-awaited USB-C display output functionality while advancing M3 support, GPU optimizations, and display pipeline improvements.
Five years after its first boot on Apple Silicon, the Asahi Linux project has achieved what many considered impossible: reliable display output through USB-C ports on M-series Macs. This breakthrough caps half a decade of reverse engineering that transformed Apple's proprietary hardware into one of the most polished ARM Linux experiences available.
The DisplayPort Breakthrough
For years, the single most frequent user question was "When will USB-C displays work?" This persistent query became an internal joke, with developers theoretically extending the estimated delivery date toward the heat death of the universe. Now, lead engineer Sven Peter has demonstrated a MacBook Air driving an external display via HDMI adapter at the 39C3 conference, powered by the experimental "fairydust" kernel branch.
This feat required reverse engineering four interdependent hardware components:
- Display Coprocessor (DCP): Manages display pipelines
- Display Crossbar (DPXBAR): Routes display signals
- Apple Type-C PHY (ATCPHY): Handles physical layer signaling
- USB-C Power Delivery Controller (ACE)
The solution remains experimental, currently supporting only one USB-C port per device and exhibiting quirks with hot-plugging and color accuracy. Developers stress this is strictly a preview for technically advanced users while refinement continues.
M3 Support Advances
Concurrently, three new contributors have accelerated support for Apple's M3 processors. Preliminary device trees and kernel patches enable booting to Plasma desktop on M3 MacBook Airs with basic functionality:
- Keyboard and touchpad operational
- Wi-Fi connectivity
- USB 3.0 support
- NVMe storage access
However, significant hurdles remain. The M3's redesigned GPU featuring ray tracing and mesh shaders differs substantially from previous generations, requiring new reverse engineering efforts. Current implementations rely on inefficient software rendering, making GPU acceleration the critical path for usable M3 support.
Display Innovations
Beyond USB-C, the team solved another display limitation: enabling 120Hz refresh rates on 14" and 16" MacBook Pro panels. New contributor Oliver Bestmann discovered that Apple's ProMotion system requires specific timestamp values in display control packets. His innovative workaround delivers smooth 120Hz output in kernel 6.18.4+, though variable refresh rate support remains future work.
Concurrent display pipeline improvements include:
- Experimental hardware plane support for efficient compositing
- Reverse engineering Apple's proprietary "Interchange" framebuffer format
- Early HDR experimentation
- Color management fixes eliminating oversaturation
Ecosystem Progress
The project continues reducing its kernel patch footprint, shrinking from 1,232 patches in 6.13.8 to 858 in 6.18.8. GPU driver upstreaming has begun with UAPI header submissions to the DRM maintainers. Significant performance optimizations include:
- Memory copy operations now running at bus speed (355GB/s on M1 Ultra)
- Aligned buffer clearing optimizations
- Vulkan copy speed doubling for large buffers
Package management improvements in Fedora Asahi Remix feature DNF5 integration with PackageKit, enabling automatic transitions to upstream packages as components merge into mainline Linux.
As Asahi Linux enters its sixth year, the project demonstrates how sustained reverse engineering can transform proprietary hardware into open-source friendly platforms. With USB-C display support achieved and M3 enablement progressing, the team continues refining what's become arguably the most complete ARM desktop Linux implementation available.
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