From: Udo A. Steinberg The chipset doc for IHC4 tells us: 1.In general, software should not attempt any non-posted accesses during arbiter disable except to the ICH4's power management registers. This implies that interrupt handlers for any unmasked hardware interrupts and SMI/NMI should check ARB_DIS status before reading from ICH devices. So it's not a good idea to access ICH devices after arbiter shut down. Signed-off-by: Udo A. Steinberg Signed-off-by: Thomas Gleixner Cc: Len Brown --- drivers/acpi/processor_idle.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) Index: linux-2.6.22-rc4-mm/drivers/acpi/processor_idle.c =================================================================== --- linux-2.6.22-rc4-mm.orig/drivers/acpi/processor_idle.c 2007-06-16 12:10:22.000000000 +0200 +++ linux-2.6.22-rc4-mm/drivers/acpi/processor_idle.c 2007-06-16 12:10:22.000000000 +0200 @@ -978,6 +978,12 @@ static int acpi_idle_enter_c3(struct cpu return 0; } + /* + * Must be done before busmaster disable as we might need to + * access HPET ! + */ + acpi_state_timer_broadcast(pr, cx, 1); + /* disable bus master */ if (pr->flags.bm_check) { spin_lock(&c3_lock); @@ -997,7 +1003,6 @@ static int acpi_idle_enter_c3(struct cpu /* Get start time (ticks) */ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); - acpi_state_timer_broadcast(pr, cx, 1); acpi_idle_do_entry(cx); t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); -- - 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/