path: root/Documentation/cpu-freq
diff options
authorViresh Kumar <>2013-01-31 02:03:53 +0000
committerRafael J. Wysocki <>2013-02-02 00:01:16 +0100
commit951fc5f45836988c7df1d05c7f4658f331e7a920 (patch)
tree196083ffadd033233faf66e0883c4662409ad569 /Documentation/cpu-freq
parent5553f9e26f6f49a93ba732fd222eac6973a4cf35 (diff)
cpufreq: Update Documentation for cpus and related_cpus
Documentation related to cpus and related_cpus is confusing and not very clear. Over that CPUFreq core has seen much changes recently. Lets update documentation and comments for cpus and related_cpus. Signed-off-by: Viresh Kumar <> Signed-off-by: Rafael J. Wysocki <>
Diffstat (limited to 'Documentation/cpu-freq')
2 files changed, 10 insertions, 4 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index c436096351f8..72f70b16d299 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -111,6 +111,12 @@ policy->governor must contain the "default policy" for
For setting some of these values, the frequency table helpers might be
helpful. See the section 2 for more information on them.
+SMP systems normally have same clock source for a group of cpus. For these the
+.init() would be called only once for the first online cpu. Here the .init()
+routine must initialize policy->cpus with mask of all possible cpus (Online +
+Offline) that share the clock. Then the core would copy this mask onto
+policy->related_cpus and will reset policy->cpus to carry only online cpus.
1.3 verify
diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt
index 04f6b32993e6..ff2f28332cc4 100644
--- a/Documentation/cpu-freq/user-guide.txt
+++ b/Documentation/cpu-freq/user-guide.txt
@@ -190,11 +190,11 @@ scaling_max_freq show the current "policy limits" (in
first set scaling_max_freq, then
-affected_cpus : List of CPUs that require software coordination
- of frequency.
+affected_cpus : List of Online CPUs that require software
+ coordination of frequency.
-related_cpus : List of CPUs that need some sort of frequency
- coordination, whether software or hardware.
+related_cpus : List of Online + Offline CPUs that need software
+ coordination of frequency.
scaling_driver : Hardware driver for cpufreq.