As the latest stable kernel version, Linux 5.18 is now officially released and brings a lot of new features – especially to better support AMD, Intel’s latest CPU and GPU products. Announcing the release of Linux 5.18 in an email, Linus Torvalds wrote: “There were no unexpected nasty surprises last week, so we’re here to release 5.18 on time”.
In the Linux 5.18 kernel, the biggest change, which is slightly controversial, is finally the inclusion of Intel’s Software Custom Chip (SDSi, a hardware “in-app” type of feature that unlocks processor add-ons through payment) into the mainline kernel. This driver restricts user support for certain processor features in the absence of certain Intel certificates.
Some users worry that Intel is exploring a new business model by launching SDSi. Under this “business model”, Intel CPU features will be disabled by default until the user “pays” an additional fee to obtain a corresponding license to “unlock” full functionality.
In an overview of the uproar, LWN’s Jonathan Corbet explained that there is no technical reason for the Intel SDSi driver, it’s purely a matter of interest. On a codebase, the implementation/support of this feature is no different from other easily included drivers, no matter how Intel rhetorically uses the “paid” features it provides.
Intel has not made clear its plans for sdsi-enabled CPU features. At least for now, users don’t need to worry too much about this feature. On the hardware side, the Raspberry Pi Zero 2w gets full mainstream Linux kernel support in this release (out of the box) and also supports Tesla’s FSD chip, a Samsung-based ARM SoC. In addition, new processors from AMD and Intel are in development.
Linux 5.18 drivers also receive tweaks to support a bunch of Razer Black Widow keyboards; support for Imagis touchscreens; support for ACPI profiles on ThinkPads with AMD processors; further improvements to Apple Magic Keyboard support, including first-gen and 2015 models Type FN keymap.
Other new features in Linux 5.18 include:
- New Hardware Feedback Interface (HFI) driver for Intel hybrid processors such as Alder Lake
- Intel Indirect Branch Tracing (IBT) as part of Control-Flow Execution Technology
- NUMA Balanced Scheduler Update for AMD EPYC Servers
- AMD HSMP driver
- Various AMD Nested Virtualization Improvements
- Intel Idle driver supports Intel Xeon ‘Sapphire Rapids’ processors
- AMD GPU drivers enable FreeSync by default
- Btrfs supports encoded I/O and faster fsync
- FN key mapping for MacBook Pro with Touch Bar
In addition, Intel PECI as a platform environment control interface has also been incorporated for the interface between CPU and BMC on Intel server platforms, and preparations for Intel IPI virtualization have also landed in 5.18, and the actual enablement should be in the v5.19 cycle in progress.
For the realm of the graphic, Linux 5.18 brings Intel DG2 G12 sub-platform support, Intel Alder Lake N graphics support, and various DG2/Alchemist preparations. For Linux 5.19, Arc Graphics DG2 / Alchemist support will arrive when the first desktop graphics cards ship in the next few months.
The new release also includes AMD EDAC readiness for Zen 4 CPUs, AMD Nested Virtualization Enhancements, and other Zen 4 architecture readiness features. Linux 5.18’s KVM now also supports AMD virtual machines with up to 511 vCPUs, up from the current 255 vCPU limit and ahead of next-generation EPYC servers using Bergamo to provide higher core counts.
Talking about AMD On the graphics side, Linux 5.18 now enables AMDGPU FreeSync “video mode” by default, while the previous kernel was hidden behind a module option. Early IP blocks are also enabled for next-generation GPUs and APUs, but more will be available in the 5.19 kernel.
For more details, you can refer to the kernel page, LWN’s merging overview ( Part 1, Part 2), Phoronix’s feature summary, and comments on the source code itself.
Unsurprisingly, Linux 5.18 will appear on the release pages soon, and the update is expected to hit Pop!_OS sometime in the near future (the distro’s policy is to “ensure users are more secure than the updated kernel provided by Ubuntu”).