The Most Prominent Linux 5.9 Kernel Features From AMD RDNA 2 To Battling Nefarious Shims

The Linux 5.9 kernel could be released as soon as today but more than likely will be pushed back to next Sunday given Torvalds' comments last week and continuing to see plenty of merge requests in recent days. But in any case when Linux 5.9 does ship very soon it comes with an abundance of new features and improvements.

While we have been covering Linux 5.9 changes since even before the merge window opened two months ago based on what had been queuing in the "-next" trees, here is a recap of some of the most interesting features/changes for this next kernel version. Below is a look at what I would say are the nine most interesting changes for Linux 5.9 while also linked below is our complete Linux 5.9 feature overview for a more exhaustive list of the kernel changes for this autumn 2020 kernel.

- Initial support for AMD RDNA 2 graphics cards in the form of Sienna Cichlid and Navy Flounder. It's terrific that AMD got their next-generation GPU support out ahead of time and will actually be in a released kernel prior to the 28 October announcement for RDNA 2 / Navi 2. But given that most Linux distributions don't immediately transition to new major kernel versions, those on the likes of Ubuntu will still be having to manually upgrade their own kernel as well as switching to the latest Mesa and LLVM for the support on launch-day if not using the pre-packaged Radeon Software for Linux driver. It's also not immediately clear how polished this RDNA 2 support is in Linux 5.9 even though there have been several rounds of fixes for Linux 5.9. Once we get our hands on the Radeon RX 6000 series hardware we will be able to tell how polished the support is in the Linux 5.9 kernel or if Linux 5.10+ is more desirable, but I am cautiously optimistic this first-cut support in 5.9 is in good enough shape for launch day.

- Intel Rocket Lake graphics support is also wired up, building off the existing Gen12 code. Intel also upstreamed more DG1 Xe graphics card support code albeit that remains a work in progress.

- Intel FSGSBASE support finally was mainlined after years of work with possible performance benefits going back to Ivy Bridge era CPUs as well as AMD CPUs.

- Various file-system improvements like performance work on Btrfs to FSCRYPT inline encryption and secure TRIM for F2FS. NVMe ZNS support also has come together for zoned namespaces with the NVMe 2.0 specification.

- Initial bring-up work for IBM POWER10 processors.

- Continued USB4 support work.

- Support for building the Linux x86 32-bit kernel using the LLVM Clang compiler, complementing the Clang support already for the Linux kernel on AArch64 and x86_64.

- ARM/ARM64 devices now default to the Schedutil CPU frequency scaling governor for making use of scheduler utilization information for making more accurate CPU performance state decisions, similar to the Intel P-State push as well for using Schedutil by default.

- A safeguard to prevent "shims" from using GPL-only symbols that in turn are being used by proprietary kernel modules, following that recent controversy.

See our complete list of Linux 5.9 kernel features via our feature overview. If you appreciate the daily Linux news coverage and timely kernel information and benchmarks consider going premium during our Oktoberfest/COVID special.