Description of problem:

From drivers/clocksource/acpi_pm.c:

u32 pmtmr_ioport __read_mostly;
...

/*
 * Allow an override of the IOPort. Stupid BIOSes do not tell us about
 * the PMTimer, but we might know where it is.
 */
static int __init parse_pmtmr(char *arg)
{
        unsigned long base;
        ...
        base = simple_strtoul(arg, &e, 16);
        ...
        pmtmr_ioport = base;
        ...
}

Version-Release number of selected component (if applicable):

Observed in 2.6.24.7-75.el5rt may as well be present on other versions