Linux 7.4 Features Steam Frame VR Headset, More AMD Zen 6 Enablement & Initial Apple M4 / A18 Pro Bring-Up

The Linux 7.4 kernel is hopefully going to be this year's Long Term Support (LTS) kernel version and is coming jam-packed with new features and changes. The Linux 7.4 merge window was the largest in kernel history and saw many new features land over the past two weeks. Here is a look at all the interesting changes from my covering of the v7.4 merge window. Some key takeaways include getting the Ryzen Zen 6 platform support ready ahead of launch, AMD PerfOpt for better performance with Radeon iGPUs, initial support for the Apple M4 and A18 Pro SoCs, AMDGPU HDMI 2.1 is enabled by default, a new driver for Nintendo Switch 2 controllers, and various performance optimizations. CPUs / Processors: - Getting AMD Ryzen Zen 6 client support in good shape with various device ID additions across the various platform drivers. - Initial support for the Apple M4 and Apple A18 Pro SoCs and Device Trees for such devices. But for Linux 7.4 the functionality remains extremely limited and not yet read for end-users. - The Google Tensor G5 is finally supported by mainline along with last year's Pixel 10 smartphones using this "Laguna" SoC. - Initial support for the Steam Frame VR headset with the basic Device Tree addition. - RISC-V more portable optimization work around misaligned user copy now able to be handled at run-time rather than configuring at kernel build-time. - AMD EPYC Zen 6 PML support for Page Modification Logging. - Intel Instruction Timeout / VM-Exit with KVM. - ARM64 on s390 for KVM virtualization as part of that IBM and Arm collaboration around dual architecture hardware. - Fixing a Ryzen AI 9 HX 370 regression due to Cache Aware Scheduling. - Power management additions for AMD Ryzen Zen 6 and Intel Rugged Panther Lake. - A hibernation improvement to help meet energy certifications. - Fixing AMD CPU TLB size reporting for Zen 5 and newer CPUs. - Improved scheduling latency for short-slice tasks. - Introduction fo the steal governor for enhancing Linux VM usage. - NVIDIA Olympus SMT optimizations benefiting Vera. - Randomly picking idle CPU cores by the scheduler when they are equally shallow. - Adapting AMD Zen 6 CPUs for less costly CPU security mitigations thanks to the introduction of the BTB CTX isolation featurhttps://www.phoronix.net/image.php?id=2026&image=linux_74_drm_mede with these processors. - Optimized AES implementations on x86 and RISC-V within the kernel crypto library. - Removal of ARM64 big endian support. - Merging the Intel BFF driver. - Support for more Qualcomm Snapdragon X2 laptops. Memory Management: - CXL preparations for Dynamic Capacity Devices "DCD" for scaling up or down the memory capacity dynamically without needing to reboot the host or physically reconfiguring the hardware. - A big speed-up for the early boot-time physical memory allocator. In one test going from around 265 seconds to about 50 milliseconds. - The MM pull brought more optimizations. - A very significant optimization to the workqueue code. - A nice performance improvement with the slab updates. - Introduction of the new Core MM tree. - Sunsetting old EDAC drivers due to the "AI generated fixes frenzy" causing a burden for upstream maintainers. - Intel Dynamic PAMT for helping Intel servers conserve memory. Graphics: - AMDGPU enables HDMI 2.1 support by default now that HDMI VRR / FreeSync and ALLM are ready. A very long-awaited addition for Radeon Linux users relying on HDMI with high refresh rates and/or high resolution displays. - AMD PerfOpt is enabled by default for providing better AI/LLM performance for Radeon iGPUs. - The Intel Xe driver now has CPU binds and ULLS on the migration queue for better performance. - The Intel Xe driver also added >a href="https://www.phoronix.com/news/Intel-Xe-vRAM-Health-Check">vRAM health checks and degraded video memory handling. - Continued work on the NVIDIA Nova Rust driver. - The MSM DRM driver for Qualcomm hardware now supports the Adreno A830, A845, A850, and X2-85.