Linux Kernel 6.6 Released. This is What’s New.

Release highlights of Linux Kernel 6.6 bring the latest CPU, GPU support, and improvements to file systems and networking.


Linus Torvalds released Linux Kernel 6.6, which is probably the last mainline Kernel of this year and will likely be featured in the major releases in 2024. As usual, you get updated fixes and hardware support in this Kernel 6.6. In addition, the key update includes the EEVDF scheduler, Nouveau user-space API update and more.

This release took around 7 RCs for the past few weeks for testing and quite long considering other Kernel releases. However, it is now available for download.

So this last week has been pretty calm, and I have absolutely no excuses to delay the v6.6 release any more, so here it is. There’s a random smattering of fixes all over, and apart from some bigger fixes to the r8152 driver, it’s all fairly small. Below is the shortlog for last week for anybody who really wants to get a flavor of the details. It’s short enough to scroll through.

Linus

Let’s briefly take a look at what’s new.

Linux Kernel 6.6: What’s New

Processor updates

Linux Mainline Kernel 6.6 marks a significant shift in processor management with the integration of the EEVDF scheduler, bidding adieu to the CFS scheduler code. This transition promises enhanced performance and efficiency, particularly benefiting AMD processors.

The release introduces AMD Dynamic Boost Control support, affording users greater control over performance optimization. This feature empowers AMD users to fine-tune their processor’s capabilities, enhancing the overall experience.

AMD Zen-based systems can now breathe easier as Linux Kernel 6.6 addresses and resolves issues that previously led to unnecessary kernel panics. This update ensures a more stable and hassle-free computing experience.

Kernel 6.6 brings a temperature and EDAC support boost specifically tailored for the AMD Family 1Ah processors. This fine-tuned integration ensures smoother operations and improved reliability, especially for Zen 5 users.

Intel and AMD CPU users benefit from the merger of Intel Shadow Stack in Kernel 6.6. This essential security feature guards against Return-Oriented Programming (ROP) attacks, fortifying systems against potential vulnerabilities.

The Kernel 6.6 reinstates Intel cluster scheduling, tailored for modern Core hybrid CPUs. This brings a significant performance boost to Intel users, optimizing their CPU’s multitasking capabilities.

Kernel 6.6 supports Intel Sapphire Rapids PECI, catering to users of these processors. This addition ensures seamless compatibility and improved system monitoring capabilities.

Users of AMD processors without Enhanced REP MOVSB/STOSB (ERMS) benefit from a micro-optimization in Kernel 6.6. This update fine-tunes CPU performance, enhancing the experience for AMD users.

GPU updates

A new feature, AMD FreeSync Panel Replay support, emerges as a fresh alternative to Panel Self Refresh for laptops. This technology empowers AMD GPU users with smoother and more dynamic visuals, enhancing the laptop viewing experience.

Linux Kernel 6.6 takes a step forward in safeguarding against potentially malicious behaviour from NVIDIA’s proprietary driver. This improvement strengthens the overall security of GPU systems, providing peace of mind for users.

AMDGPU DC extends its reach by building on RISC-V architecture for driver display code. This compatibility brings AMD GPU functionalities to a broader range of devices, expanding the possibilities for RISC-V-based systems.

The kernel introduces initial support for the Intel Lunar Lake VPU4, setting the stage for more robust multimedia capabilities on Intel Lunar Lake devices.

Kernel 6.6 continues its efforts in enabling Intel Meteor Lake graphics, ensuring that Intel users can take full advantage of their hardware for enhanced graphics performance.

The open-source Nouveau driver receives uAPI additions tailored for the NVK Vulkan driver. This update opens up new possibilities for Nouveau users, enhancing Vulkan compatibility and performance.

In addition to these notable changes, Kernel 6.6 includes various other updates to kernel graphics drivers, ensuring the GPU experience is as smooth and efficient as possible.

Misc updates

In this release, Security Enhanced Linux (SELinux) has made notable improvements. It has removed references to the US National Security Agency (NSA), which initially initiated SELinux. This move enhances the security and transparency of the SELinux framework, ensuring users a more robust security model.

The RISC-V architecture gets a security boost with Kernel 6.6, now supporting Kernel Address Space Layout Randomization (KASLR). This crucial feature randomizes the kernel’s address space layout, significantly bolstering security. Combined with other RISC-V improvements, this update fortifies the platform for a safer computing experience.

In this kernel release, the USB subsystem gets a significant update with the addition of the USB MIDI 2.0 gadget function driver. This addition expands the functionality of USB devices for MIDI applications. Furthermore, the update includes earlier Lunar Lake USB work, enhancing compatibility and performance for USB-connected devices.

Kernel 6.6 introduces the Intel Visual Sensing Controller (IVSC) driver, catering to modern laptops. This driver empowers laptops with advanced visual sensing capabilities, enhancing user experiences with features like facial recognition and gesture control.

ReiserFS, a once-popular file system, has been declared obsolete in Linux Kernel 6.6. This means that it’s on its way out and will likely be removed from future kernel versions in 2025.

Kernel 6.6 marks the end of the experimental phase for the in-kernel SMB server, KSMBD – which has been added back in 2021 via KErnel 5.15. This server can now be relied upon for stable and efficient SMB file sharing within the Linux ecosystem. Hopefully, this will resolve many SMB installation/configuration issues.

How to Download and Install Linux Kernel 6.6

Remember that using the bleeding-edge mainline Linux Kernel in your production systems/daily-drive laptops/desktops is not wiser unless you have a specific requirement.

For general users, it’s always best to wait for a few weeks until all the major Linux Distributions bring this version via their official stable channel after proper testing.

That being said, if you still want to install this version in Ubuntu and related distributions, visit the below pages:

  • Firstly, visit the mainline kernel page
    • Browse to the latest version folder (such as 6.6). There are two types of builds available – generic and lowlatency. You can download generic builds that work most of the time for standard systems.
    • For audio recordings and other setups that require low latency (like real-time feeds), download the lowlatency one.
  • Secondly, download the four deb packages for generic via the terminal and install them.
wget -c https://kernel.ubuntu.com/mainline/v6.6.1/amd64/linux-headers-6.6.1-060601-generic_6.6.1-060601.202311151749_amd64.deb

wget -c https://kernel.ubuntu.com/mainline/v6.6.1/amd64/linux-headers-6.6.1-060601_6.6.1-060601.202311151749_all.deb

wget -c https://kernel.ubuntu.com/mainline/v6.6.1/amd64/linux-image-unsigned-6.6.1-060601-generic_6.6.1-060601.202311151749_amd64.deb

wget -c https://kernel.ubuntu.com/mainline/v6.6.1/amd64/linux-modules-6.6.1-060601-generic_6.6.1-060601.202311151749_amd64.deb
sudo dpkg -i *.deb
  • After installation, reboot the system.
  • The instruction for lowlatency and other architecture (e.g., ARM) installations are the same. Replace the package name in the above wget commands. You can find them on the mainline Kernel page.

You can also compile sources on your own from the below links.

mainline:6.62023-10-30[tarball][pgp][patch][view diff][browse]

Distro support

Arch Linux users should get this version by 1st/2nd week of November 2023 via monthly ISO refresh.

Ubuntu 24.04 may feature this Kernel by April 2024.

Wrapping up

To sum up, the release of Linux Kernel 6.6 introduces numerous important updates and enhancements, such as updates to CPU and GPU, security, core changes, and improvements to file systems and networking.

This release initiates the merge window for Kernel 6.7.

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