Linux 7.2 Will Boot on Mac M3, but Only to the Serial Console

The Linux 7.2 kernel, with its merge window opening in mid-June, will be able to boot on Macs with Apple M3 chips. Developer Sven Peter has submitted the updates for the Device Tree for Apple SoCs intended for this version, which include the patches signed by Janne Grunau to establish the Device Tree files for the M3, codenamed t8122. This work comes just ahead of the third anniversary of the M3 family debut.

This is a very preliminary booting process. As Peter notes in the pull request, the patches are sufficient to boot the kernel up to a simple serial console, but more work will be needed before these machines become useful for end users.

The Device Tree covers four models: iMac 24" (M3, 2023), MacBook Air 13" and 15" (M3, 2024), and MacBook Pro 14" (M3, 2023). The set of described components is reduced to the essentials: CPU cores, interrupt controller, power states, watchdog, serial, pin controller, i2c, and boot framebuffer. For laptops, the PWM controller for keyboard illumination is added, while the iMac and MacBook Pro 14" include the Apple USB Type-C cd321x port controller, managed via i2c.

The Road is Still Long

The main hurdle remains the GPU. There is still no graphics driver in the mainline for the M3 Macs, and the desktop environment relies on slow and energy-intensive software rendering. The graphical architecture of the M3 differs significantly from that of the M1 and M2, featuring innovations like hardware ray tracing, mesh shaders, and Dynamic Caching, which extends the development time.

Currently, on M3 chips, internal SSD, display, keyboard, and trackpad work, while Wi-Fi, Bluetooth, and audio are not yet supported; the documentation page of the Asahi Linux project regarding the M3 is largely a list of items still to be defined. The small size of the team, which we discussed during the founder's farewell, also weighs heavily on the progress.

Next, there are the Apple M4 and M5 to tackle, while the M6 is expected by the end of the year. For now, on M3 Macs, Linux reaches only the serial console: daily use is still a long way off.