drivers/cpufreq/Kconfig

   1 config CPU_FREQ
   2         bool "CPU Frequency scaling"
   3         help
   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.
   7
   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.
  11
  12           For details, take a look at <file:Documentation/cpu-freq>.
  13
  14           If in doubt, say N.
  15
  16 if CPU_FREQ
  17
  18 config CPU_FREQ_TABLE
  19        def_tristate m
  20
  21 config CPU_FREQ_DEBUG
  22         bool "Enable CPUfreq debugging"
  23         help
  24           Say Y here to enable CPUfreq subsystem (including drivers)
  25           debugging. You will need to activate it via the kernel
  26           command line by passing
  27              cpufreq.debug=<value>
  28
  29           To get <value>, add
  30                1 to activate CPUfreq core debugging,
  31                2 to activate CPUfreq drivers debugging, and
  32                4 to activate CPUfreq governor debugging
  33
  34 config CPU_FREQ_STAT
  35        tristate "CPU frequency translation statistics"
  36        select CPU_FREQ_TABLE
  37        default y
  38        help
  39          This driver exports CPU frequency statistics information through sysfs
  40          file system
  41
  42 config CPU_FREQ_STAT_DETAILS
  43        bool "CPU frequency translation statistics details"
  44        depends on CPU_FREQ_STAT
  45        help
  46          This will show detail CPU frequency translation table in sysfs file
  47          system
  48
  49 choice
  50         prompt "Default CPUFreq governor"
  51         default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
  52         default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  53         help
  54           This option sets which CPUFreq governor shall be loaded at
  55           startup. If in doubt, select 'performance'.
  56
  57 config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  58         bool "performance"
  59         select CPU_FREQ_GOV_PERFORMANCE
  60         help
  61           Use the CPUFreq governor 'performance' as default. This sets
  62           the frequency statically to the highest frequency supported by
  63           the CPU.
  64
  65 config CPU_FREQ_DEFAULT_GOV_USERSPACE
  66         bool "userspace"
  67         select CPU_FREQ_GOV_USERSPACE
  68         help
  69           Use the CPUFreq governor 'userspace' as default. This allows
  70           you to set the CPU frequency manually or when an userspace
  71           program shall be able to set the CPU dynamically without having
  72           to enable the userspace governor manually.
  73
  74 endchoice
  75
  76 config CPU_FREQ_GOV_PERFORMANCE
  77        tristate "'performance' governor"
  78        help
  79           This cpufreq governor sets the frequency statically to the
  80           highest available CPU frequency.
  81
  82           If in doubt, say Y.
  83
  84 config CPU_FREQ_GOV_POWERSAVE
  85        tristate "'powersave' governor"
  86        help
  87           This cpufreq governor sets the frequency statically to the
  88           lowest available CPU frequency.
  89
  90           If in doubt, say Y.
  91
  92 config CPU_FREQ_GOV_USERSPACE
  93        tristate "'userspace' governor for userspace frequency scaling"
  94        help
  95           Enable this cpufreq governor when you either want to set the
  96           CPU frequency manually or when an userspace program shall
  97           be able to set the CPU dynamically, like on LART
  98           <http://www.lart.tudelft.nl/>
  99
 100           For details, take a look at <file:Documentation/cpu-freq/>.
 101
 102           If in doubt, say Y.
 103
 104 config CPU_FREQ_GOV_ONDEMAND
 105         tristate "'ondemand' cpufreq policy governor"
 106         help
 107           'ondemand' - This driver adds a dynamic cpufreq policy governor.
 108           The governor does a periodic polling and
 109           changes frequency based on the CPU utilization.
 110           The support for this governor depends on CPU capability to
 111           do fast frequency switching (i.e, very low latency frequency
 112           transitions).
 113
 114           For details, take a look at linux/Documentation/cpu-freq.
 115
 116           If in doubt, say N.
 117
 118 endif   # CPU_FREQ