A fresh round of kernel patches landed on the Linux mailing list this week that could make running x86 and x86_64 games on ARM64 hardware significantly more reliable. Igalia, the open-source consulting firm, posted v7 of its FUTEX set_robust_list2 and get_robust_list2 system call patches, rebased against the latest mainline kernel. The patches address shortcomings in the existing robust futex interface that have been a sticking point for FEX-Emu and other emulation layers trying to run x86 games on ARM processors.
FEX-Emu is the userspace emulator that makes it possible to run x86/x86_64 Linux binaries on ARM64 systems, and it sits at the heart of Valve's plans for Steam Play on ARM hardware. The emulator depends on these low-level kernel interfaces to correctly handle threading and synchronization in games that were never designed for ARM. Without proper robust futex support, games can hit subtle race conditions or outright crash, making the existing system calls a bottleneck for emulation fidelity.
The updated patch series, posted by Igalia developer André Almeida on 2026-09-25, includes adaptations to recent VDSO changes in the mainline kernel along with fixes for a race condition that had stalled development since late November. Igalia has been working on this effort since 2025, initially motivated by ensuring FEX-Emu operates efficiently for the kinds of workloads that Steam Play titles generate on ARM64 devices.
These patches still need to work through the kernel review process before they land in a mainline release, but their progression from v1 to v7 suggests active engagement with upstream maintainers. For anyone watching the ARM64 Linux gaming space, particularly the potential for devices like the Steam Frame VR headset, this is one of the foundational pieces of kernel infrastructure that needs to be in place before the experience can match what x86 users expect.