After 2 months of solid development, Linux 6.4 kernel is officially available to download.

Announcing the release of the latest Linux kernel on (where else?) the official Linux Kernel Mailing List (LKML), Linux founder Linus Torvalds writes:

“Most of the stuff in my mailbox the last week has been about upcoming things for 6.5 but that’s for tomorrow. For today we’re all busy build-testing the newest kernel release, and checking that it’s all good. Right?”

I’d say “yes”, Linus but I’d be lying.

So what’s new exactly?

New Features in Linux 6.4

You’d expect a new Linux kernel release to feature miscellaneous hardware enablement and bring up for ARM boards and other tech with unpronounceable names. Well, in a shocking turn of events, that’s —Nah, that’s exactly what’s on offer here.

As I’ve mentioned previously, I find it hard to get pumped about support for new Intel/AMD chips, graphics cards, etc as I’m unlikely and/or unable to use them anytime soon. Still, it’s nice to know they’re there, ready for those better placed than I to make use of bleeding-edge tech.

Filesystem finesse includes a flurry of smaller changes to the in-kernel NTFS3 file-system driver; code clean ups and small performance boost for EXT4; better directory logging and error handling in BTRFS; and F2FS filesystems now support zoned block devices where zone size is not a power of 2.

Further upstreamed Rust code features in this update, with the state of play as such that Phoronix anticipate the first usable Rust drivers in the near future.

Using Linux distros convertible Lenovo Yoga laptops gets easier with this kernel as a swathe of Lenovo Yoga notebooks, including the Yoga C940 and the Ryzen-powered Ideapad Flex 14APIaf, are supported by a new ‘tablet switch’ driver that detects when the device keyboard is folded away.

Elsewhere, Linux 6.4 includes new power features for the Steam Deck. The (stupendously successful) gaming device includes an AMD “Van Gogh” APU and Linux 6.4’s AMDGPU kernel driver introduces additional power features (which Steam OS will likely expose via a GUI at some point).

Looking forward to using Linux on RISC-V tablets and laptops? If so you’ll be pleased to hear that there’s now support for hibernation and suspend-to-disk support. Some other RISC-V work also features, including support for the Svnapot extension, and a new system to provide hardware info.

Gamers will be interested to hear that the kernel’s XPad driver now supports the Turtle Beach REACT-Raf and Turtle Beach Reconaf Xbox controllers. Chances are other models in Turtle Beach’s (extensive) lineup will either work OOTB or be able to work with a little fiddling.

A bunch of old(er) Genius branded graphics tablets get mainline support, including EasyPen M406, M506 & M406W, the MousePen 508WX & 508X, and the PenSketch T609A. On the topic of “old” stuff, the kernel has a new FireWire/IEEE 1394 (remember that?) maintainer.

Finally, Apple Silicon support continues to mature but, importantly, remains far short of bring in a daily-driver-ready state (for most use cases). Asahi Linux remains the best way to experience Linux on Apple Silicon, and it’s that work that continues to filter upstream, here in the mainline kernel.

Keyboard backlights on MacBooks with M1 and M2 chips makes it in to 6.4, while continued work on Wi-Fi 7 support benefits M1 Pro and M1 Max devices.

Other highlights:

  • Linus cleaned up x86 memory copy code
  • SLOB memory allocator removed
  • SELinux runtime disable feature, checkreqprot removed
  • Bytedance engineers bring major performance boost to VDUSE
  • Process-level samepage merging control
  • New module_memory mechanism
  • Wi-Fi drivers for Realtek rtl8710bu, rtl8822bs, rtl8822cs & rtl8821cs
  • Lenovo Yoga laptops ‘tablet mode’ switch driver

For more details you can read through Phoronix’s feature recap, or part one and part two of LWN’s always-exhaustive merge window run-throughs.

Want to download Linux 6.4 right now? You can! Source code is up in the usual places. But unless you’re super skilled at compiling things by hand you might want to wait for a distro maintainer to package up and issue the release as a software update.

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