apm_driver_version(9)

okay bestie, welcome to apm_driver_version(9) from the Kernel API Manual — it’s the little APM driver version check with “ask the BIOS what it supports” energy ✨

💖 NAME 💖

apm_driver_version — APM driver version. That’s the name, and it is literally here to grab the APM version 💅

🎀 SYNOPSIS 🎀

int apm_driver_version (u_short *val );

🦋 ARGUMENTS 🦋

• val — on return, this gets loaded with the APM version 💖

🌸 DESCRIPTION 🌸

So the whole mission is simple: retrieve the APM version supported by the BIOS. The catch? This is only supported for APM 1.1 or higher. If you get an error, that’s a big hint that APM 1.0 is probably present 💀

On entry, val should point to a value indicating the APM driver version. The high byte is the major number and the low byte is the minor number — both in BCD, no cap.

On return, val will hold the BIOS revision supported, in that same format. Iconic little round trip, honestly 🫶

🔥 SEE ALSO 🔥

Kernel file ./arch/x86/kernel/apm_32.c, plus this whole bestie squad:

• apm_error(9)
• __apm_bios_call(9)
• apm_bios_call(9)
• __apm_bios_call_simple(9)
• apm_bios_call_simple(9)
• apm_get_event(9)
• set_power_state(9)
• set_system_power_state(9)
• apm_do_idle(9)
• apm_do_busy(9)
• apm_cpu_idle(9)
• apm_power_off(9)
• apm_enable_power_management(9)
• apm_get_power_status(9)
• apm_engage_power_management(9)
• apm_console_blank(9)

xoxo, from ./arch/x86/kernel, dated October 2026 — stay slay, stay APM-aware 💜