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_GOV_COMMON 21 bool 22 23config CPU_FREQ_STAT 24 tristate "CPU frequency translation statistics" 25 default y 26 help 27 This driver exports CPU frequency statistics information through sysfs 28 file system. 29 30 To compile this driver as a module, choose M here: the 31 module will be called cpufreq_stats. 32 33 If in doubt, say N. 34 35config CPU_FREQ_STAT_DETAILS 36 bool "CPU frequency translation statistics details" 37 depends on CPU_FREQ_STAT 38 help 39 This will show detail CPU frequency translation table in sysfs file 40 system. 41 42 If in doubt, say N. 43 44choice 45 prompt "Default CPUFreq governor" 46 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ 47 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE 48 help 49 This option sets which CPUFreq governor shall be loaded at 50 startup. If in doubt, select 'performance'. 51 52config CPU_FREQ_DEFAULT_GOV_PERFORMANCE 53 bool "performance" 54 select CPU_FREQ_GOV_PERFORMANCE 55 help 56 Use the CPUFreq governor 'performance' as default. This sets 57 the frequency statically to the highest frequency supported by 58 the CPU. 59 60config CPU_FREQ_DEFAULT_GOV_POWERSAVE 61 bool "powersave" 62 depends on EXPERT 63 select CPU_FREQ_GOV_POWERSAVE 64 help 65 Use the CPUFreq governor 'powersave' as default. This sets 66 the frequency statically to the lowest frequency supported by 67 the CPU. 68 69config CPU_FREQ_DEFAULT_GOV_USERSPACE 70 bool "userspace" 71 select CPU_FREQ_GOV_USERSPACE 72 help 73 Use the CPUFreq governor 'userspace' as default. This allows 74 you to set the CPU frequency manually or when a userspace 75 program shall be able to set the CPU dynamically without having 76 to enable the userspace governor manually. 77 78config CPU_FREQ_DEFAULT_GOV_ONDEMAND 79 bool "ondemand" 80 select CPU_FREQ_GOV_ONDEMAND 81 select CPU_FREQ_GOV_PERFORMANCE 82 help 83 Use the CPUFreq governor 'ondemand' as default. This allows 84 you to get a full dynamic frequency capable system by simply 85 loading your cpufreq low-level hardware driver. 86 Be aware that not all cpufreq drivers support the ondemand 87 governor. If unsure have a look at the help section of the 88 driver. Fallback governor will be the performance governor. 89 90config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 91 bool "conservative" 92 select CPU_FREQ_GOV_CONSERVATIVE 93 select CPU_FREQ_GOV_PERFORMANCE 94 help 95 Use the CPUFreq governor 'conservative' as default. This allows 96 you to get a full dynamic frequency capable system by simply 97 loading your cpufreq low-level hardware driver. 98 Be aware that not all cpufreq drivers support the conservative 99 governor. If unsure have a look at the help section of the 100 driver. Fallback governor will be the performance governor. 101endchoice 102 103config CPU_FREQ_GOV_PERFORMANCE 104 tristate "'performance' governor" 105 help 106 This cpufreq governor sets the frequency statically to the 107 highest available CPU frequency. 108 109 To compile this driver as a module, choose M here: the 110 module will be called cpufreq_performance. 111 112 If in doubt, say Y. 113 114config CPU_FREQ_GOV_POWERSAVE 115 tristate "'powersave' governor" 116 help 117 This cpufreq governor sets the frequency statically to the 118 lowest available CPU frequency. 119 120 To compile this driver as a module, choose M here: the 121 module will be called cpufreq_powersave. 122 123 If in doubt, say Y. 124 125config CPU_FREQ_GOV_USERSPACE 126 tristate "'userspace' governor for userspace frequency scaling" 127 help 128 Enable this cpufreq governor when you either want to set the 129 CPU frequency manually or when a userspace program shall 130 be able to set the CPU dynamically, like on LART 131 <http://www.lartmaker.nl/>. 132 133 To compile this driver as a module, choose M here: the 134 module will be called cpufreq_userspace. 135 136 For details, take a look at <file:Documentation/cpu-freq/>. 137 138 If in doubt, say Y. 139 140config CPU_FREQ_GOV_ONDEMAND 141 tristate "'ondemand' cpufreq policy governor" 142 select CPU_FREQ_GOV_COMMON 143 help 144 'ondemand' - This driver adds a dynamic cpufreq policy governor. 145 The governor does a periodic polling and 146 changes frequency based on the CPU utilization. 147 The support for this governor depends on CPU capability to 148 do fast frequency switching (i.e, very low latency frequency 149 transitions). 150 151 To compile this driver as a module, choose M here: the 152 module will be called cpufreq_ondemand. 153 154 For details, take a look at linux/Documentation/cpu-freq. 155 156 If in doubt, say N. 157 158config CPU_FREQ_GOV_CONSERVATIVE 159 tristate "'conservative' cpufreq governor" 160 depends on CPU_FREQ 161 select CPU_FREQ_GOV_COMMON 162 help 163 'conservative' - this driver is rather similar to the 'ondemand' 164 governor both in its source code and its purpose, the difference is 165 its optimisation for better suitability in a battery powered 166 environment. The frequency is gracefully increased and decreased 167 rather than jumping to 100% when speed is required. 168 169 If you have a desktop machine then you should really be considering 170 the 'ondemand' governor instead, however if you are using a laptop, 171 PDA or even an AMD64 based computer (due to the unacceptable 172 step-by-step latency issues between the minimum and maximum frequency 173 transitions in the CPU) you will probably want to use this governor. 174 175 To compile this driver as a module, choose M here: the 176 module will be called cpufreq_conservative. 177 178 For details, take a look at linux/Documentation/cpu-freq. 179 180 If in doubt, say N. 181 182config GENERIC_CPUFREQ_CPU0 183 tristate "Generic CPU0 cpufreq driver" 184 depends on HAVE_CLK && REGULATOR && PM_OPP && OF 185 help 186 This adds a generic cpufreq driver for CPU0 frequency management. 187 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) 188 systems which share clock and voltage across all CPUs. 189 190 If in doubt, say N. 191 192menu "x86 CPU frequency scaling drivers" 193depends on X86 194source "drivers/cpufreq/Kconfig.x86" 195endmenu 196 197menu "ARM CPU frequency scaling drivers" 198depends on ARM 199source "drivers/cpufreq/Kconfig.arm" 200endmenu 201 202menu "AVR32 CPU frequency scaling drivers" 203depends on AVR32 204 205config AVR32_AT32AP_CPUFREQ 206 bool "CPU frequency driver for AT32AP" 207 depends on PLATFORM_AT32AP 208 default n 209 help 210 This enables the CPU frequency driver for AT32AP processors. 211 If in doubt, say N. 212 213endmenu 214 215menu "CPUFreq processor drivers" 216depends on IA64 217 218config IA64_ACPI_CPUFREQ 219 tristate "ACPI Processor P-States driver" 220 depends on ACPI_PROCESSOR 221 help 222 This driver adds a CPUFreq driver which utilizes the ACPI 223 Processor Performance States. 224 225 For details, take a look at <file:Documentation/cpu-freq/>. 226 227 If in doubt, say N. 228 229endmenu 230 231menu "MIPS CPUFreq processor drivers" 232depends on MIPS 233 234config LOONGSON2_CPUFREQ 235 tristate "Loongson2 CPUFreq Driver" 236 help 237 This option adds a CPUFreq driver for loongson processors which 238 support software configurable cpu frequency. 239 240 Loongson2F and it's successors support this feature. 241 242 For details, take a look at <file:Documentation/cpu-freq/>. 243 244 If in doubt, say N. 245 246endmenu 247 248menu "PowerPC CPU frequency scaling drivers" 249depends on PPC32 || PPC64 250source "drivers/cpufreq/Kconfig.powerpc" 251endmenu 252 253menu "SPARC CPU frequency scaling drivers" 254depends on SPARC64 255config SPARC_US3_CPUFREQ 256 tristate "UltraSPARC-III CPU Frequency driver" 257 help 258 This adds the CPUFreq driver for UltraSPARC-III processors. 259 260 For details, take a look at <file:Documentation/cpu-freq>. 261 262 If in doubt, say N. 263 264config SPARC_US2E_CPUFREQ 265 tristate "UltraSPARC-IIe CPU Frequency driver" 266 help 267 This adds the CPUFreq driver for UltraSPARC-IIe processors. 268 269 For details, take a look at <file:Documentation/cpu-freq>. 270 271 If in doubt, say N. 272endmenu 273 274menu "SH CPU Frequency scaling" 275depends on SUPERH 276config SH_CPU_FREQ 277 tristate "SuperH CPU Frequency driver" 278 help 279 This adds the cpufreq driver for SuperH. Any CPU that supports 280 clock rate rounding through the clock framework can use this 281 driver. While it will make the kernel slightly larger, this is 282 harmless for CPUs that don't support rate rounding. The driver 283 will also generate a notice in the boot log before disabling 284 itself if the CPU in question is not capable of rate rounding. 285 286 For details, take a look at <file:Documentation/cpu-freq>. 287 288 If unsure, say N. 289endmenu 290 291endif 292endmenu 293