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SubjectRe: [stable] [PATCH] ACPI: Move timer broadcast and pmtimer access before C3 arbiter shutdown
* Andrew Morton (akpm@linux-foundation.org) wrote:
> hm, this needs a bit of help to get it to work against Len's current tree.

Here's some help, compile tested only. Udo/Thomas, was this found to
be root cause of a real bug? I didn't want this to get lost if it's
still meant to be relevant for -stable.

thanks,
-chris
--

Subject: ACPI: Move timer broadcast and pmtimer access before C3 arbiter shutdown

From: Udo A. Steinberg <us15@os.inf.tu-dresden.de>

The chip set doc for IHC4 says:

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 <us15@os.inf.tu-dresden.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[chrisw: rebase against Len's changes in -mm]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

---

drivers/acpi/processor_idle.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2c6a3cb..15db3e8 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -978,6 +978,11 @@ static int acpi_idle_enter_c3(struct cpuidle_device *dev,
return 0;
}

+ /* 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);
+
/* disable bus master */
if (pr->flags.bm_check) {
spin_lock(&c3_lock);
@@ -995,10 +1000,6 @@ static int acpi_idle_enter_c3(struct cpuidle_device *dev,
ACPI_FLUSH_CPU_CACHE();
}

- /* 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);

if (pr->flags.bm_check) {
-
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