[ 3.8.y.z extended stable ] Patch "acpi-cpufreq: set current frequency based on target P-State" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    acpi-cpufreq: set current frequency based on target P-State

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 75bacd58a18c2562ad105d990f9fc9f8c023e90a Mon Sep 17 00:00:00 2001
From: Ross Lagerwall <rosslagerwall at gmail.com>
Date: Fri, 31 May 2013 20:45:17 +0100
Subject: acpi-cpufreq: set current frequency based on target P-State

commit 8673b83bf2f013379453b4779047bf3c6ae387e4 upstream.

Commit 4b31e774 (Always set P-state on initialization) fixed bug
#4634 and caused the driver to always set the target P-State at
least once since the initial P-State may not be the desired one.
Commit 5a1c0228 (cpufreq: Avoid calling cpufreq driver's target()
routine if target_freq == policy->cur) caused a regression in
this behavior.

This fixes the regression by setting policy->cur based on the CPU's
target frequency rather than the CPU's current reported frequency
(which may be different).  This means that the P-State will be set
initially if the CPU's target frequency is different from the
governor's target frequency.

This fixes an issue where setting the default governor to
performance wouldn't correctly enable turbo mode on all cores.

Signed-off-by: Ross Lagerwall <rosslagerwall at gmail.com>
Reviewed-by: Len Brown <len.brown at intel.com>
Acked-by: Viresh Kumar <viresh.kumar at linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/cpufreq/acpi-cpufreq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 7b0d49d..73e273e 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -347,11 +347,11 @@ static u32 get_cur_val(const struct cpumask *mask)
 	switch (per_cpu(acfreq_data, cpumask_first(mask))->cpu_feature) {
 	case SYSTEM_INTEL_MSR_CAPABLE:
 		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
-		cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
+		cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
 		break;
 	case SYSTEM_AMD_MSR_CAPABLE:
 		cmd.type = SYSTEM_AMD_MSR_CAPABLE;
-		cmd.addr.msr.reg = MSR_AMD_PERF_STATUS;
+		cmd.addr.msr.reg = MSR_AMD_PERF_CTL;
 		break;
 	case SYSTEM_IO_CAPABLE:
 		cmd.type = SYSTEM_IO_CAPABLE;
--
1.8.1.2