Linux Kernel 5.15 Released. This is What’s New

3 min

A quiet “Halloween” release yet impactful Linux Kernel 5.15 is here improving Processors, Storage, Graphics and other components. Here’s a release recap and how to download and install for Ubuntu.

Linux Kernel 5.15
Linux Kernel 5.15

Linux Torvalds released Linux Kernel 5.15 on Oct 31, 2021 on Halloween 2021. This release introduces some important features to mainline Linux Kernel, among others. The NTFS driver (NTFS3) from Paragon Software is now mainlined, also includes Apple M1 Soc Support, in-kernel SMB driver for file sharing and more.

Quoting Linus –

It’s been calm, and I have no excuse to add an extra rc, so here we are, with v5.15 pushed out, and the merge window starting tomorrow.

Anyway, the last week of 5.15 was mainly networking and gpu fixes, with some random sprinkling of other things (a few btrfs reverts, some kvm updates, minor other fixes here and there – a few architecture fixes, couple of tracing, small driver fixes etc). Full shortlog appended.

This release may have started out with some -Werror pain, but it calmed down fairly quickly and on the whole 5.15 was fair small and calm. Let’s hope for more of the same – without Werror issues this time – for the upcoming merge window.


Although we covered the initial set of features during RC1 a while back, here’s a recap of the new features for you.

Linux Kernel 5.15 – New Features


  • Optimized C3 Cache handling by setting proper switches in AMD processors.
  • AMD PTDMA driver is merged in this Kernel release, supporting high bandwidth memory-to-memory and I/O copy operations.
  • AMD Processors causing serious resume issues when waking up from suspending for certain Laptop models. A fix landed in this kernel release.
  • AMD SB-RMI Driver and AMD Zen 3 APU temperature monitoring is merged.
  • Some final pieces of support for Intel Alder Lake Processor, which was in the works for quite some time.
  • Initial support added in this Kernel for Intel’s Xe HP and DG2/Alchemist GPUs.


  • A bunch of AMD RDNA2 Graphics card initial support lands in this release.
  • Radeon “Cyan Skillfish” Navi 1x APU support lands in this release.
  • Intel submits initial code for XeHP and DG2 discrete graphics card. The patch also includes updates to DRM Scheduler, fixes for Alder Lake P and Alder Lake S and updates to Gen12 graphics.
  • Intel also drops Cannon Lake graphics support.

Storage Systems

  • Probably the most important of this Kernel release is the new NTFS driver, replacing the older one.
  • Developed by Paragon Software, this driver is expected to bring certain awaited features such as creation date of NTFS files and folders from Windows drive.
  • Other notable storage updates includes –
  • Optimization and improvements to XFS, EXT4, F2FS, Btrfs.
  • A fix for floppy disk driver code also came in this release.
  • This Kernel first to introduce in-Kernel SMB Driver for file sharing. This has several benefits as it is now part of Kernel and lightweight than SAMBA.

Other Updates

  • Apple M1 IOMMU driver is merged, bringing more support for Apple M1 SoC in Linux. This IOMMU driver was created by the community as part of the “Asahi Linux” project. This driver is expected to get the display driver, USB and PCI interfaces working in Apple M1 chips.
  • AMAZON’s DAMON (Data Access Monitor) – memory management framework is mainlined to improve performance while reducing memory overhead. Read the entire implementation here.
  • Some ARM board updates including NVIDIA Jetson TX2 NX suport.
  • New Realtek RTL8188EU WiFi driver support.
  • Cirrus Logic Dolphin audio support also included in this Kernel release.

Download and Install

How to Install in Ubuntu

You can install the mainline kernel packages from the below link right now in your latest Ubuntu or Ubuntu-based Linux distributions. But it is not recommended installing this as it might break the current Ubuntu Linux system whichever you are running (e.g Ubuntu 20.04 LTS). If you are running Debian, Ubuntu, and other stable releases – do not upgrade using the below steps. Instead, wait for an official update via your Linux distribution.

For general users, unless you are keen to experiment with the latest hardware whose support is added in this release, you should not update at the moment.

If you still want to install the latest Linux Kernel 5.15, follow the below instructions to install in Ubuntu-based systems.

Visit the mainline kernel page.

There are two types of builds available – generic and lowlatency. For common systems, you can download generic builds that work most of the time. For audio recordings and other setups that require low latency, download the lowlatency one.

Download below four packages for generic via terminal and install.

wget -c
wget -c
wget -c
wget -c
sudo dpkg -i *.deb

After installation, reboot the system.

The instruction for lowlatency and other architecture (ARM) installations are the same. Replace the package name in the above wget commands. You can find them on the mainline Kernel page.

If you are using Arch Linux, or Arch-based distribution, it is expected that Linux Kernel 5.15 release packages arrive within the October 2021 first week during monthly Arch .iso refresh.

Ubuntu 22.04 LTS and next Fedora release is expected to ship this Kernel – I assume. But I am still wondering as 5.15 is not the LTS Kernel, hence it may not be included in Ubuntu 22.04 LTS, instead a later version.

With this release, the merge window opens for next Linux Kernel 5.16.


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