ATRTC(4)

💖 NAME 💖

atrtc — the AT Real-Time Clock (RTC) driver, aka the little clock chip that's been holding it down since forever 🕰️✨

🎀 SYNOPSIS 🎀

okay so bestie, this driver is a mandatory part of i386/amd64 kernels. like, you don't get to opt out. it's just there. iconic behavior fr fr 👑

The following tunables are settable from the loader(8):

• hint.atrtc.X.clock — this one controls event timers functionality support. set it to 0 and you've disabled it. default value is 1. simple as that 💅
• hw.atrtc.enable — this one forces enabling or disabling of the device(s). setting it to 0 disables it, setting it to 1 enables it, and doing so bypasses any platform configuration hints (yeah, it just ignores them, main character energy 😌). default value is -1 (autodetect). so like, by default it figures itself out. respect.

✨ DESCRIPTION ✨

So this driver uses the RTC hardware to supply the kernel with a time-of-day clock with 1 second resolution plus one event timer. that's the whole gig. lowkey humble but highkey essential 🫶

This hardware uses a base frequency of 32768Hz for advancing the time-of-day clock and generating periodic interrupts. and the way it makes interrupts?? it does it with a fixed number of frequencies, ranging from 2Hz to 8192Hz, obtained by dividing that base frequency by one of the supported power-of-2 divisors. math girlies stay winning 🌸

One thing to know: the event timer provided by the driver is irrelevant to CPU power states. like, it does not care. it's not plugged into that whole situation. periodt 💀

🌈 SEE ALSO 🌈

• apic(4)
• attimer(4)
• eventtimers(4)
• hpet(4)

okay that's the whole page bestie, go forth and know ur RTC 💖 this one's from Debian, dated September 17, 2010 — yeah she's a vintage queen and she still slays ✨🎀🦋