For Linux users with specialized keyboards or complex macro needs, a persistent quirk has lingered since the early days of the kernel: the absence of default mapping for function keys F13 through F24 on PS/2 keyboards. That era ends with Linux 6.17. A crucial patch from Werner Sembach at TUXEDO Computers has been merged, ensuring these keys—often used for custom shortcuts or featured on industrial and niche hardware—are now recognized out-of-the-box.

Why F13-F24 Matter

While most consumer keyboards top out at F12, higher function keys serve critical roles:
- Macro & Customization: Software developers and power users leverage F13-F24 for application-specific shortcuts, avoiding conflicts with common F1-F12 bindings.
- Legacy Hardware: Keyboards like the Unicomp PC 122 (below) include dedicated F13-F24 keys, previously requiring manual setkeycodes workarounds on Linux.
- Virtual Mapping: Modern apps and gaming environments often repurpose these keys for background functions or layered input.

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Technical Breakthrough

Sembach's patch resolves two core issues:
1. Scancode Clarity: F24 shared a scancode with Zenkaku/Hankaku (a Japanese IME key), but real-world usage showed Zenkaku/Hankaku typically used the tilde (~) scancode instead. The driver now prioritizes F24.
2. Unmapped Range: F13-F22 were entirely unmapped, preventing userspace tools from assigning them reliably. The patch fills this gap, enabling seamless customization.

Broader Input Driver Enhancements

Beyond function keys, Linux 6.17's input merge includes:
- Synaptics RMI: New capacity buttons and forcepad functionality for precision touchpads.
- Goodix Touchscreens: Added polling mode support for robust input capture.
- FocalTech FT8716: Compatibility for newer touch controllers.
- Samsung Keypad & evdev: General reliability and event-handling improvements.

A Small Fix with Big Implications

This decades-overdue correction exemplifies Linux's iterative refinement—even "minor" fixes enhance professionalism for specialized workflows. For keyboard enthusiasts, developers crafting intricate input layers, or enterprises using legacy hardware, Linux 6.17 erases a quiet frustration. As Sembach noted, the change harmonizes with ongoing userspace adjustments in Qt, KDE, and xkeyboard-config, ensuring the ecosystem fully capitalizes on these once-orphaned keys.

Source: Phoronix by Michael Larabel