This is a note to let you know that I've just added the patch titled
PM / QoS: CPU C-state breakage with PM Qos change
to the 3.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pm-qos-cpu-c-state-breakage-with-pm-qos-change.patch
and it can be found in the queue-3.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From d020283dc694c9ec31b410f522252f7a8397e67d Mon Sep 17 00:00:00 2001
From: Venkatesh Pallipadi <[email protected]>
Date: Fri, 3 Feb 2012 22:22:25 +0100
Subject: PM / QoS: CPU C-state breakage with PM Qos change
From: Venkatesh Pallipadi <[email protected]>
commit d020283dc694c9ec31b410f522252f7a8397e67d upstream.
Looks like change "PM QoS: Move and rename the implementation files"
merged during the 3.2 development cycle made PM QoS depend on
CONFIG_PM which depends on (PM_SLEEP || PM_RUNTIME).
That breaks CPU C-states with kernels not having these CONFIGs, causing CPUs
to spend time in Polling loop idle instead of going into deep C-states,
consuming way way more power. This is with either acpi idle or intel idle
enabled.
Either CONFIG_PM should be enabled with any pm_qos users or
the !CONFIG_PM pm_qos_request() should return sane defaults not to break
the existing users. Here's is the patch for the latter option.
[rjw: Modified the changelog slightly.]
Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/pm_qos.h | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -107,7 +107,19 @@ static inline void pm_qos_remove_request
{ return; }
static inline int pm_qos_request(int pm_qos_class)
- { return 0; }
+{
+ switch (pm_qos_class) {
+ case PM_QOS_CPU_DMA_LATENCY:
+ return PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
+ case PM_QOS_NETWORK_LATENCY:
+ return PM_QOS_NETWORK_LAT_DEFAULT_VALUE;
+ case PM_QOS_NETWORK_THROUGHPUT:
+ return PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE;
+ default:
+ return PM_QOS_DEFAULT_VALUE;
+ }
+}
+
static inline int pm_qos_add_notifier(int pm_qos_class,
struct notifier_block *notifier)
{ return 0; }
Patches currently in stable-queue which might be from [email protected] are
queue-3.2/pm-qos-cpu-c-state-breakage-with-pm-qos-change.patch
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