Linux 6.2 Features: Stable Intel Arc Graphics. RTX 30 Support, Intel On Demand + IFS Ready

Now that the merge window for Linux 6.2 is over, here is a look at all the prominent features on deck for the Linux 6.2 kernel that will be released as stable in about eight weeks.

Linux 6.2 is quite a hearty release and will represent the first major kernel update of 2023 when it debuts in February. With the Linux 6.2 kernel the Intel DG2/Alchemist graphics are now treated as stable / no longer behind a module flag, there is initial NVIDIA RTX 30 / Ampere GPU support in the open-source Nouveau driver, AMD Zen 4 pipeline utilization metrics added, updated Zstd compression code in the kernel, the Intel IFS driver is now deemed stable / no longer "broken" as it was on past kernels, Call Depth Tracking is available for reducing the mitigation cost of Retbleed on Skylake era CPUs (benchmarks coming this week!), preparations for WiFi 7 as well as 800 Gbps wired networking, preparing the Intel On Demand (Software Defined Silicon) for CPU licensed feature activation model with upcoming Intel CPUs, more Rust code has been merged, and the introduction of the new AI / compute accelerator subsystem.

Here is the more extensive look at the prominent Linux 6.2 features overall.

Processors / Architectures:

- AMD Zen 4 pipeline utilization data is now exposed for perf to help developers/administrators in profiling and finding performance bottlenecks with new Ryzen 7000 series and EPYC 9004 series processors.

- Ampere Altra's SMPro co-processor has seens everal drivers upstreamed for Linux 6.2.

- Fixing the broken strcmp() implementation for Motorola 68000 series that turns out has always been broken in a subtle way for the m68k.

- A scalability improvement for large IBM Power systems.

- RISC-V support for persistent memory devices.

- Intel's Linear Address Masking (LAM) feature had been proposed and shortly merged to Linux Git but then un-pulled it with Linus Torvalds being upset over some fundamental issues with the Intel LAM code. So it's not in Linux 6.2 now and will need to be re-worked.

- The Intel IFS driver has been fixed up for this In-Field Scan feature for providing CPU silicon testing capabilities with upcoming Intel CPUs.

- Intel On Demand Driver is ready for use with more functionality implemented as well as now labeling it Intel On Demand rather than the former "Software Defined Silicon" naming. Intel On Demand / Software Defined Silicon is the controversial feature for licensed activation of certain CPU features in upcoming Xeon Scalable processors.

- Intel TDX guest attestation support has been merged as the latest Trust Domain Extensions (TDX) work.

- KVM prepares for exposing new Intel CPU instructions.

- A power savings tweak for Alder Lake N and Raptor Lake P processors.

- Intel SGX Async Exit Notification "AEX Notify" support for helping fend off some forms of SGX (Secure Guard Extensions) attacks.

- Various AArch64 improvements such as dynamic shadow call stack support.

- A new control for the split-lock detector due to a prior kernel change around split-lock detection/enforcement hurting the performance of some Steam Play games.

- Support for more Qualcomm Snapdragon SoCs as well as the Apple M1 Pro/Ultra/Max has now been mainlined. With the Apple Silicon enablement push is also the new CPUFreq driver being merged.

- AmpereOne mitigation for Spectre-BHB.

Graphics:

- Initial NVIDIA RTX 30 "Ampere" GPU acceleration within the Nouveau driver but the performance is still extremely poor.

- Energy sensor monitoring support for DG2/Alchemist graphics via the HWMON interfaces.

- Continued enablement around Meteor Lake graphics support.

- Intel DG2/Alchemist graphics are stable with no longer being hidden behind a module flag for enabling. This affects current Intel Arc Graphics, Flex Series, and other DG2-based Intel GPUs.

- Various other DRM graphics driver updates.

- FBDEV support for the "nomodeset" option.

- Raspberry Pi 4K @ 60Hz display support.

- Allwinner A100 and D1 display support within the Sun4i DRM driver.

- Tieing into the graphics DRM code is the new compute accelerator "accel" subsystem/framework.