drivers/cpufreq/Kconfig

   1 menu "CPU Frequency scaling"
   2
   3 config 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
  18 if CPU_FREQ
  19
  20 config CPU_FREQ_TABLE
  21         tristate
  22
  23 config 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
  36 config 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
  45 choice
  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
  53 config 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
  61 config 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
  70 config 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
  79 config 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
  91 config 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.
 102 endchoice
 103
 104 config 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
 115 config 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
 126 config 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
 141 config 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
 159 config 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
 182 menu "x86 CPU frequency scaling drivers"
 183 depends on X86
 184 source "drivers/cpufreq/Kconfig.x86"
 185 endmenu
 186
 187 menu "ARM CPU frequency scaling drivers"
 188 depends on ARM
 189 source "drivers/cpufreq/Kconfig.arm"
 190 endmenu
 191
 192 menu "PowerPC CPU frequency scaling drivers"
 193 depends on PPC32 || PPC64
 194 source "drivers/cpufreq/Kconfig.powerpc"
 195 endmenu
 196
 197 endif
 198 endmenu