ATRTC(4)

🎀 ATRTC(4) — AT Real-Time Clock (RTC) driver 🎀

okay so this is ATRTC(4) from the Kernel Interfaces Manual, and it’s the AT Real-Time Clock (RTC) driver page — iconic, mandatory, and lowkey the reason your kernel knows what time it is. 💅

💖 NAME 💖

atrtc — AT Real-Time Clock (RTC) driver

✨ SYNOPSIS ✨

This driver is a mandatory part of i386/amd64 kernels.

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

• hint.atrtc.X.clock — controls event timers functionality support. Setting to 0, disables it. Default value is 1.
• hw.atrtc.enabled — Forces enabling or disabling of the device(s). Setting to 0 disables it, setting to 1 enables it, bypassing any platform configuration hints. Default value is -1 (autodetect).

🦋 DESCRIPTION 🦋

This driver uses RTC hardware to supply the kernel with a time-of-day clock with 1 second resolution and one event timer. This hardware uses a base frequency of 32768Hz for advancing the time-of-day clock and generating periodic interrupts. Interrupts could be generated with a fixed number of frequencies, from 2Hz to 8192Hz, obtained by dividing the base frequency by one of the supported power-of-2 divisors.

The event timer provided by the driver is irrelevant to CPU power states — like, it’s literally not in that conversation, bestie.

🎀 SEE ALSO 🎀

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

💖 Debian · December 15, 2022 · ATRTC(4) — that’s the page, bestie, periodt. 💅