ACPI: disable lower idle C-states across suspend/resume

changeset b04e7bdb984e3b7f62fb7f44146a529f88cc7639 from mainline.

device_suspend() calls ACPI suspend functions, which seems to have undesired
side effects on lower idle C-states. It took me some time to realize that
especially the VAIO BIOSes (both Andrews jinxed UP and my elfstruck SMP one)
show this effect. I'm quite sure that other bug reports against suspend/resume
about turning the system into a brick have the same root cause.

After fishing in the dark for quite some time, I realized that removing the ACPI
processor module before suspend (this removes the lower C-state functionality)
made the problem disappear. Interestingly enough the propability of having a
bricked box is influenced by various factors (interrupts, size of the ram image,
...). Even adding a bunch of printks in the wrong places made the problem go
away. The previous periodic tick implementation simply pampered over the
problem, which explains why the dyntick / clockevents changes made this more
prominent.

We avoid complex functionality during the boot process and we have to do the
same during suspend/resume. It is a similar scenario and equaly fragile.

Add suspend / resume functions to the ACPI processor code and disable the lower
idle C-states across suspend/resume. Fall back to the default idle
implementation (halt) instead.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index f7de02a6f497a5d61752dff2a413a7c7b4c9f43a..e529f4c2bbe2becbaab0fd15f3ebd19fb1641e58 100644 (file)
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -93,6 +93,8 @@ static struct acpi_driver acpi_processor_driver = {
                .add = acpi_processor_add,
                .remove = acpi_processor_remove,
                .start = acpi_processor_start,
+               .suspend = acpi_processor_suspend,
+               .resume = acpi_processor_resume,
                },
 };
 

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 80ffc782991631492d08c2dea2837972698e5193..13915e8d81cae6f0f92accd31f9c61ac89d89e62 100644 (file)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -324,6 +324,23 @@ static void acpi_state_timer_broadcast(struct acpi_processor *pr,
 
 #endif
 
+/*
+ * Suspend / resume control
+ */
+static int acpi_idle_suspend;
+
+int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
+{
+       acpi_idle_suspend = 1;
+       return 0;
+}
+
+int acpi_processor_resume(struct acpi_device * device)
+{
+       acpi_idle_suspend = 0;
+       return 0;
+}
+
 static void acpi_processor_idle(void)
 {
        struct acpi_processor *pr = NULL;
@@ -354,7 +371,7 @@ static void acpi_processor_idle(void)
        }
 
        cx = pr->power.state;
-       if (!cx) {
+       if (!cx || acpi_idle_suspend) {
                if (pm_idle_save)
                        pm_idle_save();
                else

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index b4b0ffdab098f50c5e1bb44f12400150e8ff923c..0276fc6ec5f8f6a42bbf08e9d6effb5b36bbfbb9 100644 (file)
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -279,6 +279,8 @@ int acpi_processor_power_init(struct acpi_processor *pr,
 int acpi_processor_cst_has_changed(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr,
                              struct acpi_device *device);
+int acpi_processor_suspend(struct acpi_device * device, pm_message_t state);
+int acpi_processor_resume(struct acpi_device * device);
 
 /* in processor_thermal.c */
 int acpi_processor_get_limit_info(struct acpi_processor *pr);