Linux 7.4’s merge window brought a broad set of changes to the kernel, including early platform support for AMD Zen 6 processors, Apple’s M4 and A18 Pro chips, and the Steam Frame VR headset. The release may become this year’s Long Term Support kernel, though that is not confirmed in the available information.
AMD Zen 6 support has advanced through device ID additions across platform drivers. The update also includes AMD EPYC Zen 6 support for Page Modification Logging and a new BTB context-isolation feature intended to reduce the cost of CPU security mitigations. The kernel also fixes TLB size reporting for Zen 5 and newer AMD processors.
Apple M4 and A18 Pro support is at an early stage, with device trees added but functionality still described as extremely limited and unsuitable for end users. The Google Tensor G5 is now supported in mainline Linux, including in Pixel 10 phones using the “Laguna” chip. For Steam Frame, the change is a basic device-tree addition.
Graphics updates include enabling HDMI 2.1 support by default in AMDGPU, following work on VRR, FreeSync and ALLM. AMD PerfOpt is also enabled by default to improve AI and large language model performance on Radeon integrated graphics. Intel’s Xe driver gains CPU binds and ULLS on the migration queue, as well as video memory health checks and handling for degraded memory. Qualcomm’s MSM DRM driver adds support for the Adreno A830, A845, A850 and X2-85.
Other changes span memory management and performance. CXL work prepares for Dynamic Capacity Devices, which can adjust memory capacity without a host reboot or physical hardware reconfiguration. One test of a faster early-boot physical memory allocator reduced the reported time from about 265 seconds to around 50 milliseconds. The kernel also adds a steal governor for virtual machines, scheduler changes for choosing between equally idle CPU cores, and optimized AES implementations for x86 and RISC-V.
Sources: Phoronix.