1menu "CPU Frequency scaling" 2 3config CPU_FREQ 4 bool "CPU Frequency scaling" 5 help 6 CPU Frequency scaling allows you to change the clock speed of 7 CPUs on the fly. This is a nice method to save power, because 8 the lower the CPU clock speed, the less power the CPU consumes. 9 10 Note that this driver doesn't automatically change the CPU 11 clock speed, you need to either enable a dynamic cpufreq governor 12 (see below) after boot, or use a userspace tool. 13 14 For details, take a look at <file:Documentation/cpu-freq>. 15 16 If in doubt, say N. 17 18if CPU_FREQ 19 20config CPU_FREQ_TABLE 21 tristate 22 23config CPU_FREQ_GOV_COMMON 24 bool 25 26config CPU_FREQ_STAT 27 tristate "CPU frequency translation statistics" 28 select CPU_FREQ_TABLE 29 default y 30 help 31 This driver exports CPU frequency statistics information through sysfs 32 file system. 33 34 To compile this driver as a module, choose M here: the 35 module will be called cpufreq_stats. 36 37 If in doubt, say N. 38 39config CPU_FREQ_STAT_DETAILS 40 bool "CPU frequency translation statistics details" 41 depends on CPU_FREQ_STAT 42 help 43 This will show detail CPU frequency translation table in sysfs file 44 system. 45 46 If in doubt, say N. 47 48choice 49 prompt "Default CPUFreq governor" 50 default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 51 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE 52 help 53 This option sets which CPUFreq governor shall be loaded at 54 startup. If in doubt, select 'performance'. 55 56config CPU_FREQ_DEFAULT_GOV_PERFORMANCE 57 bool "performance" 58 select CPU_FREQ_GOV_PERFORMANCE 59 help 60 Use the CPUFreq governor 'performance' as default. This sets 61 the frequency statically to the highest frequency supported by 62 the CPU. 63 64config CPU_FREQ_DEFAULT_GOV_POWERSAVE 65 bool "powersave" 66 depends on EXPERT 67 select CPU_FREQ_GOV_POWERSAVE 68 help 69 Use the CPUFreq governor 'powersave' as default. This sets 70 the frequency statically to the lowest frequency supported by 71 the CPU. 72 73config CPU_FREQ_DEFAULT_GOV_USERSPACE 74 bool "userspace" 75 select CPU_FREQ_GOV_USERSPACE 76 help 77 Use the CPUFreq governor 'userspace' as default. This allows 78 you to set the CPU frequency manually or when a userspace 79 program shall be able to set the CPU dynamically without having 80 to enable the userspace governor manually. 81 82config CPU_FREQ_DEFAULT_GOV_ONDEMAND 83 bool "ondemand" 84 select CPU_FREQ_GOV_ONDEMAND 85 select CPU_FREQ_GOV_PERFORMANCE 86 help 87 Use the CPUFreq governor 'ondemand' as default. This allows 88 you to get a full dynamic frequency capable system by simply 89 loading your cpufreq low-level hardware driver. 90 Be aware that not all cpufreq drivers support the ondemand 91 governor. If unsure have a look at the help section of the 92 driver. Fallback governor will be the performance governor. 93 94config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 95 bool "conservative" 96 select CPU_FREQ_GOV_CONSERVATIVE 97 select CPU_FREQ_GOV_PERFORMANCE 98 help 99 Use the CPUFreq governor 'conservative' as default. This allows 100 you to get a full dynamic frequency capable system by simply 101 loading your cpufreq low-level hardware driver. 102 Be aware that not all cpufreq drivers support the conservative 103 governor. If unsure have a look at the help section of the 104 driver. Fallback governor will be the performance governor. 105endchoice 106 107config CPU_FREQ_GOV_PERFORMANCE 108 tristate "'performance' governor" 109 help 110 This cpufreq governor sets the frequency statically to the 111 highest available CPU frequency. 112 113 To compile this driver as a module, choose M here: the 114 module will be called cpufreq_performance. 115 116 If in doubt, say Y. 117 118config CPU_FREQ_GOV_POWERSAVE 119 tristate "'powersave' governor" 120 help 121 This cpufreq governor sets the frequency statically to the 122 lowest available CPU frequency. 123 124 To compile this driver as a module, choose M here: the 125 module will be called cpufreq_powersave. 126 127 If in doubt, say Y. 128 129config CPU_FREQ_GOV_USERSPACE 130 tristate "'userspace' governor for userspace frequency scaling" 131 help 132 Enable this cpufreq governor when you either want to set the 133 CPU frequency manually or when a userspace program shall 134 be able to set the CPU dynamically, like on LART 135 <http://www.lartmaker.nl/>. 136 137 To compile this driver as a module, choose M here: the 138 module will be called cpufreq_userspace. 139 140 For details, take a look at <file:Documentation/cpu-freq/>. 141 142 If in doubt, say Y. 143 144config CPU_FREQ_GOV_ONDEMAND 145 tristate "'ondemand' cpufreq policy governor" 146 select CPU_FREQ_TABLE 147 select CPU_FREQ_GOV_COMMON 148 help 149 'ondemand' - This driver adds a dynamic cpufreq policy governor. 150 The governor does a periodic polling and 151 changes frequency based on the CPU utilization. 152 The support for this governor depends on CPU capability to 153 do fast frequency switching (i.e, very low latency frequency 154 transitions). 155 156 To compile this driver as a module, choose M here: the 157 module will be called cpufreq_ondemand. 158 159 For details, take a look at linux/Documentation/cpu-freq. 160 161 If in doubt, say N. 162 163config CPU_FREQ_GOV_CONSERVATIVE 164 tristate "'conservative' cpufreq governor" 165 depends on CPU_FREQ 166 select CPU_FREQ_GOV_COMMON 167 help 168 'conservative' - this driver is rather similar to the 'ondemand' 169 governor both in its source code and its purpose, the difference is 170 its optimisation for better suitability in a battery powered 171 environment. The frequency is gracefully increased and decreased 172 rather than jumping to 100% when speed is required. 173 174 If you have a desktop machine then you should really be considering 175 the 'ondemand' governor instead, however if you are using a laptop, 176 PDA or even an AMD64 based computer (due to the unacceptable 177 step-by-step latency issues between the minimum and maximum frequency 178 transitions in the CPU) you will probably want to use this governor. 179 180 To compile this driver as a module, choose M here: the 181 module will be called cpufreq_conservative. 182 183 For details, take a look at linux/Documentation/cpu-freq. 184 185 If in doubt, say N. 186 187config GENERIC_CPUFREQ_CPU0 188 bool "Generic CPU0 cpufreq driver" 189 depends on HAVE_CLK && REGULATOR && PM_OPP && OF 190 select CPU_FREQ_TABLE 191 help 192 This adds a generic cpufreq driver for CPU0 frequency management. 193 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) 194 systems which share clock and voltage across all CPUs. 195 196 If in doubt, say N. 197 198menu "x86 CPU frequency scaling drivers" 199depends on X86 200source "drivers/cpufreq/Kconfig.x86" 201endmenu 202 203menu "ARM CPU frequency scaling drivers" 204depends on ARM 205source "drivers/cpufreq/Kconfig.arm" 206endmenu 207 208menu "PowerPC CPU frequency scaling drivers" 209depends on PPC32 || PPC64 210source "drivers/cpufreq/Kconfig.powerpc" 211endmenu 212 213endif 214endmenu 215