linux/drivers/cpufreq/Kconfig
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   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_STAT
  24        tristate "CPU frequency translation statistics"
  25        select CPU_FREQ_TABLE
  26        default y
  27        help
  28          This driver exports CPU frequency statistics information through sysfs
  29          file system.
  30
  31          To compile this driver as a module, choose M here: the
  32          module will be called cpufreq_stats.
  33
  34          If in doubt, say N.
  35
  36config CPU_FREQ_STAT_DETAILS
  37        bool "CPU frequency translation statistics details"
  38        depends on CPU_FREQ_STAT
  39        help
  40          This will show detail CPU frequency translation table in sysfs file
  41          system.
  42
  43          If in doubt, say N.
  44
  45choice
  46        prompt "Default CPUFreq governor"
  47        default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
  48        default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  49        help
  50          This option sets which CPUFreq governor shall be loaded at
  51          startup. If in doubt, select 'performance'.
  52
  53config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  54        bool "performance"
  55        select CPU_FREQ_GOV_PERFORMANCE
  56        help
  57          Use the CPUFreq governor 'performance' as default. This sets
  58          the frequency statically to the highest frequency supported by
  59          the CPU.
  60
  61config CPU_FREQ_DEFAULT_GOV_POWERSAVE
  62        bool "powersave"
  63        depends on EXPERT
  64        select CPU_FREQ_GOV_POWERSAVE
  65        help
  66          Use the CPUFreq governor 'powersave' as default. This sets
  67          the frequency statically to the lowest frequency supported by
  68          the CPU.
  69
  70config CPU_FREQ_DEFAULT_GOV_USERSPACE
  71        bool "userspace"
  72        select CPU_FREQ_GOV_USERSPACE
  73        help
  74          Use the CPUFreq governor 'userspace' as default. This allows
  75          you to set the CPU frequency manually or when a userspace 
  76          program shall be able to set the CPU dynamically without having
  77          to enable the userspace governor manually.
  78
  79config CPU_FREQ_DEFAULT_GOV_ONDEMAND
  80        bool "ondemand"
  81        select CPU_FREQ_GOV_ONDEMAND
  82        select CPU_FREQ_GOV_PERFORMANCE
  83        help
  84          Use the CPUFreq governor 'ondemand' as default. This allows
  85          you to get a full dynamic frequency capable system by simply
  86          loading your cpufreq low-level hardware driver.
  87          Be aware that not all cpufreq drivers support the ondemand
  88          governor. If unsure have a look at the help section of the
  89          driver. Fallback governor will be the performance governor.
  90
  91config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
  92        bool "conservative"
  93        select CPU_FREQ_GOV_CONSERVATIVE
  94        select CPU_FREQ_GOV_PERFORMANCE
  95        help
  96          Use the CPUFreq governor 'conservative' as default. This allows
  97          you to get a full dynamic frequency capable system by simply
  98          loading your cpufreq low-level hardware driver.
  99          Be aware that not all cpufreq drivers support the conservative
 100          governor. If unsure have a look at the help section of the
 101          driver. Fallback governor will be the performance governor.
 102endchoice
 103
 104config CPU_FREQ_GOV_PERFORMANCE
 105        tristate "'performance' governor"
 106        help
 107          This cpufreq governor sets the frequency statically to the
 108          highest available CPU frequency.
 109
 110          To compile this driver as a module, choose M here: the
 111          module will be called cpufreq_performance.
 112
 113          If in doubt, say Y.
 114
 115config CPU_FREQ_GOV_POWERSAVE
 116        tristate "'powersave' governor"
 117        help
 118          This cpufreq governor sets the frequency statically to the
 119          lowest available CPU frequency.
 120
 121          To compile this driver as a module, choose M here: the
 122          module will be called cpufreq_powersave.
 123
 124          If in doubt, say Y.
 125
 126config CPU_FREQ_GOV_USERSPACE
 127        tristate "'userspace' governor for userspace frequency scaling"
 128        help
 129          Enable this cpufreq governor when you either want to set the
 130          CPU frequency manually or when a userspace program shall
 131          be able to set the CPU dynamically, like on LART 
 132          <http://www.lartmaker.nl/>.
 133
 134          To compile this driver as a module, choose M here: the
 135          module will be called cpufreq_userspace.
 136
 137          For details, take a look at <file:Documentation/cpu-freq/>.
 138
 139          If in doubt, say Y.
 140
 141config CPU_FREQ_GOV_ONDEMAND
 142        tristate "'ondemand' cpufreq policy governor"
 143        select CPU_FREQ_TABLE
 144        help
 145          'ondemand' - This driver adds a dynamic cpufreq policy governor.
 146          The governor does a periodic polling and 
 147          changes frequency based on the CPU utilization.
 148          The support for this governor depends on CPU capability to
 149          do fast frequency switching (i.e, very low latency frequency
 150          transitions). 
 151
 152          To compile this driver as a module, choose M here: the
 153          module will be called cpufreq_ondemand.
 154
 155          For details, take a look at linux/Documentation/cpu-freq.
 156
 157          If in doubt, say N.
 158
 159config CPU_FREQ_GOV_CONSERVATIVE
 160        tristate "'conservative' cpufreq governor"
 161        depends on CPU_FREQ
 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
 182menu "x86 CPU frequency scaling drivers"
 183depends on X86
 184source "drivers/cpufreq/Kconfig.x86"
 185endmenu
 186
 187menu "ARM CPU frequency scaling drivers"
 188depends on ARM
 189source "drivers/cpufreq/Kconfig.arm"
 190endmenu
 191
 192menu "PowerPC CPU frequency scaling drivers"
 193depends on PPC32 || PPC64
 194source "drivers/cpufreq/Kconfig.powerpc"
 195endmenu
 196
 197endif
 198endmenu
 199
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