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

       Event timer provided by the driver is irrelevant to CPU power states.

SEE ALSO

       apic(4), attimer(4), eventtimers(4), hpet(4)

Debian                                         September 17, 2010                                       ATRTC(4)