Hi,
on a Thinkpad 600X I noticed the CPU getting very hot. It turned
out that pm_idle was never called (which invokes the ACPI pm_idle
call in this case) and default_idle was used instead.
/* arch/i386/kernel/process.c, line 723 */
void cpu_idle (void)
{
/* endless idle loop with no priority at all */
while (1) {
void (*idle)(void) = pm_idle;
if (!idle)
idle = default_idle; /* once on bootup */
irq_stat[smp_processor_id()].idle_timestamp = jiffies;
while (!need_resched())
idle();
schedule(); /* never reached */
}
}
The schedule() is never reached (need_resched() is never 0) and
so the idle-variable is not updated. pm_idle is NULL on the
first call to cpu_idle on this thinkpad, and so I stay idling
in the default_idle()-function.
By moving the "void *idle = pm_idle; if(!idle)..." in the inner
while()-loop the notebook calls pm_idle (as it get's updated by ACPI)
and stays cool.
Chris
-- Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. -- Rich Cook - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Jul 31 2003 - 22:00:49 EST