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
30 config CPU_FREQ_PROC_INTF
31 tristate "/proc/cpufreq interface (deprecated)"
32 depends on CPU_FREQ && PROC_FS
34 This enables the /proc/cpufreq interface for controlling
35 CPUFreq. Please note that it is recommended to use the sysfs
36 interface instead (which is built automatically).
38 For details, take a look at <file:Documentation/cpu-freq/>.
43 prompt "Default CPUFreq governor"
45 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE if !CPU_FREQ_SA1100 && !CPU_FREQ_SA1110
46 default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
48 This option sets which CPUFreq governor shall be loaded at
49 startup. If in doubt, select 'performance'.
51 config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
53 select CPU_FREQ_GOV_PERFORMANCE
55 Use the CPUFreq governor 'performance' as default. This sets
56 the frequency statically to the highest frequency supported by
59 config CPU_FREQ_DEFAULT_GOV_USERSPACE
61 select CPU_FREQ_GOV_USERSPACE
63 Use the CPUFreq governor 'userspace' as default. This allows
64 you to set the CPU frequency manually or when an userspace
65 program shall be able to set the CPU dynamically without having
66 to enable the userspace governor manually.
70 config CPU_FREQ_GOV_PERFORMANCE
71 tristate "'performance' governor"
74 This cpufreq governor sets the frequency statically to the
75 highest available CPU frequency.
79 config CPU_FREQ_GOV_POWERSAVE
80 tristate "'powersave' governor"
83 This cpufreq governor sets the frequency statically to the
84 lowest available CPU frequency.
88 config CPU_FREQ_GOV_USERSPACE
89 tristate "'userspace' governor for userspace frequency scaling"
92 Enable this cpufreq governor when you either want to set the
93 CPU frequency manually or when an userspace program shall
94 be able to set the CPU dynamically, like on LART
95 <http://www.lart.tudelft.nl/>
97 For details, take a look at <file:Documentation/cpu-freq/>.
101 config CPU_FREQ_24_API
102 bool "/proc/sys/cpu/ interface (2.4. / OLD)"
103 depends on CPU_FREQ_GOV_USERSPACE
106 This enables the /proc/sys/cpu/ sysctl interface for controlling
107 the CPUFreq,"userspace" governor. This is the same interface
108 as known from the 2.4.-kernel patches for CPUFreq, and offers
109 the same functionality as long as "userspace" is the
110 selected governor for the specified CPU.
112 For details, take a look at <file:Documentation/cpu-freq/>.
116 config CPU_FREQ_GOV_ONDEMAND
117 tristate "'ondemand' cpufreq policy governor"
120 'ondemand' - This driver adds a dynamic cpufreq policy governor.
121 The governor does a periodic polling and
122 changes frequency based on the CPU utilization.
123 The support for this governor depends on CPU capability to
124 do fast frequency switching (i.e, very low latency frequency
127 For details, take a look at linux/Documentation/cpu-freq.