[patch 01/19] ACPI: Add support for FADT P_LVL2_UP flag

Greg Kroah-Hartman
2005-12-23T22:50:36Z

[-- Attachment #1: acpi-add-support-for-fadt-p_lvl2_up-flag.patch --]
[-- Type: text/plain, Size: 1829 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------
From: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>

[ACPI] Add support for FADT P_LVL2_UP flag
which tells us if C2 is valid for UP-only, or SMP.

As there is no separate bit for C3, use P_LVL2_UP
bit to cover both C2 and C3.

http://bugzilla.kernel.org/show_bug.cgi?id=5165

(cherry picked from 28b86b368af3944eb383078fc5797caf2dc8ce44 commit)

Signed-off-by: Venkatesh Pallipadi<venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/acpi/processor_idle.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

--- linux-2.6.14.4.orig/drivers/acpi/processor_idle.c
+++ linux-2.6.14.4/drivers/acpi/processor_idle.c
@@ -261,6 +261,16 @@ static void acpi_processor_idle(void)

cx->usage++;

+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system. We do it here instead of doing it at _CST/P_LVL
+ * detection phase, to work cleanly with logical CPU hotplug.
+ */
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && acpi_fadt.plvl2_up)
+ cx->type = ACPI_STATE_C1;
+#endif
/*
* Sleep:
* ------
@@ -527,6 +537,15 @@ static int acpi_processor_get_power_info
pr->power.states[ACPI_STATE_C0].valid = 1;
pr->power.states[ACPI_STATE_C1].valid = 1;

+#ifndef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system.
+ */
+ if ((num_online_cpus() > 1) && acpi_fadt.plvl2_up)
+ return_VALUE(-ENODEV);
+#endif
+
/* determine C2 and C3 address from pblk */
pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;

--