Changeset 9690:8d5eec311f25
---------------------------
dev: Add support for disabling ticking and the divider in MC146818

Some Linux versions disable updates (regB.set = 1) to prevent the chip
from updating its internal state while the OS is updating it. Support
for this was already there, this patch merely disables the check in
writeReg that prevented it from being enabled. The patch also includes
support for disabling the divider, which is used to control when clock
updates should start after setting the internal RTC state.

These changes are required to boot most vanilla Linux distributions
that update the RTC settings at boot.

Quick regressions pass (with the exception of 02.insttest and 40.m5threads-test-atomic where I can't find the binaries) for all supported architectures. Booting Debian Squeeze in KVM mode on X86 works after applying the patch (but not before).