It turns out that Ubuntu 22.04 LTS plans to use Linux kernel 5.15 as the default kernel. Makes sense since Linux 5.15 is also a long term support kernel, but unfortunate since Ubuntu LTS releases haven’t always used LTS kernel releases and v5.15 will have already six months old by the time the “Jammy Jellyfish” ships in April. It’s an especially unfortunate choice for those with recent hardware, but at least there’s Ubuntu’s main kernel PPA and other non available by default.
In the discussion of Ubuntu 22.04 GNOME plans, it was mentioned by Sebastien Bacher of Canonical that “the plan is to use 5.15 for the LTS but the oem and hwe variants will get 5.17 at some point.”
So if this plan is followed, by default Linux 5.15 for Ubuntu 22.04 LTS would be in 2023 with Ubuntu 22.04.2 LTS the new Ubuntu 22.10 hardware activation kernel which would provide newer kernel etc. Ubuntu OEM partners like Dell also have the ability to ship a newer kernel for their latest preloaded Linux systems.
Linux 5.15 makes sense for Ubuntu 22.04 since both are Long Term Support (LTS) releases. Linux 5.15 LTS debuted in late October, with Linux 5.16 debuting last week, and then Linux 5.17 slated for release around the end of March. Linux 5.17 would be too close to be seen by default in Ubuntu 22.04 anyway, but there’s a lot on the table that’s now missing in the default kernel.
Linux 5.16 brings Alder Lake S graphics enabled by default (we’ll probably see Ubuntu’s kernel config changed to force probe given its importance), FUTEX2 system call futex_waitv which will be important for Wine/Steam Play games at future, I/O optimizations, much more adequate support for the AMD Ryzen 6000 mobile series, Intel AMX support which will be important for Xeon Sapphire Rapids servers with the Ubuntu LTS release, and many other additions and improvements hardware support. (Similarly, a lot on the table for Linux 5.17.) Some of the PCI ID fixes/additions may be backported to Linux 5.15 or carried over to the Ubuntu kernel build, but probably none of the most important stuff. It’s a never-ending vicious circle with all drivers being part of the kernel and open source software continually advancing.
Planning for Ubuntu 22.04 LTS collage with Linux 5.15 LTS. (Pictured: Ubuntu founder Mark Shuttleworth having fun sticking to a wall at OSCON 2007.)
So while Linux 5.15 LTS makes logistical sense for Ubuntu 22.04 LTS, Linux enthusiasts in particular and those who want to run Ubuntu on the very latest Intel/AMD hardware would be better off using a version of 3rd party/unofficial kernel until new HWE kernels in future jammy jellyfish point releases. Fortunately, the Ubuntu mainline kernel PPA provides convenient mainline kernel versions of Linux 5.16 or Linux 5.17 at the time of the official Ubuntu 22.04 release, among other third-party kernel/PPA versions. With Canonical wanting to make Ubuntu “the best Linux desktop for gaming”, they might find a more approved/friendly way to run the newer mainstream Linux stable releases on Ubuntu, given the benefits of the graphics driver and other benefits enthusiasts/gamers will find in newer kernels.