An Early Look At Linux 6.4 Features: AMD CDX, AMD GAM, Intel LAM, Apple M2 & More

There is two weeks to go until the Linux 6.3 stable kernel is released, which could drag out to three weeks if last minute issues come about in the kernel. But given all the material queuing via the many "-next" code branches, we already have a good idea for many of the features in store for Linux 6.4.

While the Linux 6.4 merge window won't be kicking off until the end of April or early May, below is a look at many of the features expected for this next kernel version. The list is based on my monitoring of the many subsystem "-next" branches for seeing what's likely coming for v6.4 -- barring any last minute problems from being uncovered or objections from Linus Torvalds.

So some of what's expected for Linux 6.4 when released this summer includes:

- Initial Apple M2 bits have been mainlined including the Device Tree files for the 2022 MacBook Air, 2022 MacBook Pro 13-inch, and 2023 Mac Mini. However, due to some missing functionality, this support on the upstream kernel for Linux 6.4 won't exactly be usable for end-users... But it's moving in the right direction.

- 36+ more ASUS motherboards will enjoy sensor monitoring support with driver improvements set for Linux 6.4.

- Intel LAM support for Linear Address Masking will try once again to be mainlined.

- Intel CET Shadow Stack support looks to be mainlined for Linux 6.4.

- The Qualcomm QAIC accelerator driver is being introduced as the latest to join the recent Linux accelerator subsystem.

- 4K support for the Rockchip DRM driver.

- More Intel Meteor Lake graphics preparations.

- More Intel Habana Labs Gaudi2 code is going into that AI driver with Linux 6.4.

- DRM deadline hints for graphics drivers to help influence the GPU frequency/performance characteristics.

- Speed binning for the Panfrost DRM driver as well as supporting new MediaTek SoCs.

- Initial enablement pieces for AMD's multi-XCC CDNA accelerator have started for Linux 6.4 but further work is still needed to land.

- The AMD CDX bus is being introduced as an interface between APUs and FPGAs.

- AMD P-State Guided Autonomous Mode as another improvement/alternative over P-State EPP that appeared in Linux 6.3.

- The AMD graphics driver has new power features for the Steam Deck.

- Intel IAA 2.0 accelerator preparations.

- Intel Lunar Lake audio support.

- AMD SFH Ambient Color Sensor support.

- Intel Sierra Forest EDAC support.

- Suspend/resume fixes for some AMD Picasso laptops.

- Better MSI laptop support thanks to the MSI-EC driver landing.

- Improved Btrfs scrub code that is ~10% faster as a nice improvement there.

- Improved concurrent I/O performance with the Device Mapper.

- A tablet mode switch driver for Lenovo Yoga laptops to properly notify user-space on 2-in-1/convertible laptops when switching over to tablet orientation.

- The Novatek i2c touchscreen driver that has been used by some Android tablets over the years.

- Fixing a Nintendo controller driver issue where in effect the controllers were being turned into vibrators by rumbling indefinitely.

- Support for several Kye/Genius drawing tablets.

- Turtle Beach REACT-R and Recon Xbox controller support.

- PCMCIA/CardBus to USB drivers are set to be removed as part of clearing out unused/unmaintained PCMCIA drivers.

- Dropping the SLOB memory allocator is on the table.

- Dropping a very old workaround for far outdated Linux distributions.

- The in-kernel Zstd code will hopefully be updated.