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From: Greg KH on 19 Feb 2010 12:10
2.6.32-stable review patch. If anyone has any objections, please let us know.

------------------

From: Arjan van de Ven <arjan(a)linux.intel.com>

commit 370d5cd88509b93b76eb2f5f97efbd71c25061cb upstream.

Since the rewrite of the CPU idle governor in 2.6.32, two laptops have
surfaced where the BIOS advertises a C2 power state, but for some reason
this state is not functioning (as verified in both cases by powertop
before the patch in .32).

The old governor had the accidental behavior that if a non-working state
was chosen too many times, it would end up falling back to C1. The new
governor works differently and this accidental behavior is no longer
there; the result is a high temperature on these two machines.

This patch adds these 2 machines to the DMI table for C state anomalies;
by just not using C2 both these machines are better off (the TSC can be
used instead of the pm timer, giving a performance boost for example).

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14742

Signed-off-by: Arjan van de Ven <arjan(a)linux.intel.com>
Reported-by: <akwatts(a)ymail.com>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
Signed-off-by: Len Brown <len.brown(a)intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
drivers/acpi/processor_idle.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -110,6 +110,14 @@ static struct dmi_system_id __cpuinitdat
DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
(void *)2},
+ { set_max_cstate, "Pavilion zv5000", {
+ DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
+ DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
+ (void *)1},
+ { set_max_cstate, "Asus L8400B", {
+ DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
+ (void *)1},
{},
};



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