2 bool "CPU Frequency scaling"
4 CPU Frequency scaling allows you to change the clock speed of
5 CPUs on the fly. This is a nice method to save power, because
6 the lower the CPU clock speed, the less power the CPU consumes.
8 Note that this driver doesn't automatically change the CPU
9 clock speed, you need to either enable a dynamic cpufreq governor
10 (see below) after boot, or use a userspace tool.
12 For details, take a look at <file:Documentation/cpu-freq>.
17 bool "Enable CPUfreq debugging"
20 Say Y here to enable CPUfreq subsystem (including drivers)
21 debugging. You will need to activate it via the kernel
22 command line by passing
26 1 to activate CPUfreq core debugging,
27 2 to activate CPUfreq drivers debugging, and
28 4 to activate CPUfreq governor debugging
31 tristate "CPU frequency translation statistics"
32 depends on CPU_FREQ && CPU_FREQ_TABLE
35 This driver exports CPU frequency statistics information through sysfs
38 config CPU_FREQ_STAT_DETAILS
39 bool "CPU frequency translation statistics details"
40 depends on CPU_FREQ && CPU_FREQ_STAT
43 This will show detail CPU frequency translation table in sysfs file
47 prompt "Default CPUFreq governor"
49 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE if !CPU_FREQ_SA1100 && !CPU_FREQ_SA1110
50 default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
52 This option sets which CPUFreq governor shall be loaded at
53 startup. If in doubt, select 'performance'.
55 config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
57 select CPU_FREQ_GOV_PERFORMANCE
59 Use the CPUFreq governor 'performance' as default. This sets
60 the frequency statically to the highest frequency supported by
63 config CPU_FREQ_DEFAULT_GOV_USERSPACE
65 select CPU_FREQ_GOV_USERSPACE
67 Use the CPUFreq governor 'userspace' as default. This allows
68 you to set the CPU frequency manually or when an userspace
69 program shall be able to set the CPU dynamically without having
70 to enable the userspace governor manually.
74 config CPU_FREQ_GOV_PERFORMANCE
75 tristate "'performance' governor"
78 This cpufreq governor sets the frequency statically to the
79 highest available CPU frequency.
83 config CPU_FREQ_GOV_POWERSAVE
84 tristate "'powersave' governor"
87 This cpufreq governor sets the frequency statically to the
88 lowest available CPU frequency.
92 config CPU_FREQ_GOV_USERSPACE
93 tristate "'userspace' governor for userspace frequency scaling"
96 Enable this cpufreq governor when you either want to set the
97 CPU frequency manually or when an userspace program shall
98 be able to set the CPU dynamically, like on LART
99 <http://www.lart.tudelft.nl/>
101 For details, take a look at <file:Documentation/cpu-freq/>.
105 config CPU_FREQ_GOV_ONDEMAND
106 tristate "'ondemand' cpufreq policy governor"
109 'ondemand' - This driver adds a dynamic cpufreq policy governor.
110 The governor does a periodic polling and
111 changes frequency based on the CPU utilization.
112 The support for this governor depends on CPU capability to
113 do fast frequency switching (i.e, very low latency frequency
116 For details, take a look at linux/Documentation/cpu-freq.