Kconfig 5.2 KB

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  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. Note that this driver doesn't automatically change the CPU
  8. clock speed, you need to either enable a dynamic cpufreq governor
  9. (see below) after boot, or use a userspace tool.
  10. To compile this driver as a module, choose M here: the
  11. module will be called cpufreq.
  12. For details, take a look at <file:Documentation/cpu-freq>.
  13. If in doubt, say N.
  14. if CPU_FREQ
  15. config CPU_FREQ_TABLE
  16. tristate
  17. config CPU_FREQ_DEBUG
  18. bool "Enable CPUfreq debugging"
  19. help
  20. Say Y here to enable CPUfreq subsystem (including drivers)
  21. debugging. You will need to activate it via the kernel
  22. command line by passing
  23. cpufreq.debug=<value>
  24. To get <value>, add
  25. 1 to activate CPUfreq core debugging,
  26. 2 to activate CPUfreq drivers debugging, and
  27. 4 to activate CPUfreq governor debugging
  28. config CPU_FREQ_STAT
  29. tristate "CPU frequency translation statistics"
  30. select CPU_FREQ_TABLE
  31. default y
  32. help
  33. This driver exports CPU frequency statistics information through sysfs
  34. file system.
  35. To compile this driver as a module, choose M here: the
  36. module will be called cpufreq_stats.
  37. If in doubt, say N.
  38. config CPU_FREQ_STAT_DETAILS
  39. bool "CPU frequency translation statistics details"
  40. depends on CPU_FREQ_STAT
  41. help
  42. This will show detail CPU frequency translation table in sysfs file
  43. system.
  44. If in doubt, say N.
  45. # Note that it is not currently possible to set the other governors (such as ondemand)
  46. # as the default, since if they fail to initialise, cpufreq will be
  47. # left in an undefined state.
  48. choice
  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. config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  56. bool "performance"
  57. select CPU_FREQ_GOV_PERFORMANCE
  58. help
  59. Use the CPUFreq governor 'performance' as default. This sets
  60. the frequency statically to the highest frequency supported by
  61. the CPU.
  62. config CPU_FREQ_DEFAULT_GOV_USERSPACE
  63. bool "userspace"
  64. select CPU_FREQ_GOV_USERSPACE
  65. help
  66. Use the CPUFreq governor 'userspace' as default. This allows
  67. you to set the CPU frequency manually or when an userspace
  68. program shall be able to set the CPU dynamically without having
  69. to enable the userspace governor manually.
  70. endchoice
  71. config CPU_FREQ_GOV_PERFORMANCE
  72. tristate "'performance' governor"
  73. help
  74. This cpufreq governor sets the frequency statically to the
  75. highest available CPU frequency.
  76. To compile this driver as a module, choose M here: the
  77. module will be called cpufreq_performance.
  78. If in doubt, say Y.
  79. config CPU_FREQ_GOV_POWERSAVE
  80. tristate "'powersave' governor"
  81. help
  82. This cpufreq governor sets the frequency statically to the
  83. lowest available CPU frequency.
  84. To compile this driver as a module, choose M here: the
  85. module will be called cpufreq_powersave.
  86. If in doubt, say Y.
  87. config CPU_FREQ_GOV_USERSPACE
  88. tristate "'userspace' governor for userspace frequency scaling"
  89. help
  90. Enable this cpufreq governor when you either want to set the
  91. CPU frequency manually or when an userspace program shall
  92. be able to set the CPU dynamically, like on LART
  93. <http://www.lartmaker.nl/>.
  94. To compile this driver as a module, choose M here: the
  95. module will be called cpufreq_userspace.
  96. For details, take a look at <file:Documentation/cpu-freq/>.
  97. If in doubt, say Y.
  98. config CPU_FREQ_GOV_ONDEMAND
  99. tristate "'ondemand' cpufreq policy governor"
  100. select CPU_FREQ_TABLE
  101. help
  102. 'ondemand' - This driver adds a dynamic cpufreq policy governor.
  103. The governor does a periodic polling and
  104. changes frequency based on the CPU utilization.
  105. The support for this governor depends on CPU capability to
  106. do fast frequency switching (i.e, very low latency frequency
  107. transitions).
  108. To compile this driver as a module, choose M here: the
  109. module will be called cpufreq_ondemand.
  110. For details, take a look at linux/Documentation/cpu-freq.
  111. If in doubt, say N.
  112. config CPU_FREQ_GOV_CONSERVATIVE
  113. tristate "'conservative' cpufreq governor"
  114. depends on CPU_FREQ
  115. help
  116. 'conservative' - this driver is rather similar to the 'ondemand'
  117. governor both in its source code and its purpose, the difference is
  118. its optimisation for better suitability in a battery powered
  119. environment. The frequency is gracefully increased and decreased
  120. rather than jumping to 100% when speed is required.
  121. If you have a desktop machine then you should really be considering
  122. the 'ondemand' governor instead, however if you are using a laptop,
  123. PDA or even an AMD64 based computer (due to the unacceptable
  124. step-by-step latency issues between the minimum and maximum frequency
  125. transitions in the CPU) you will probably want to use this governor.
  126. To compile this driver as a module, choose M here: the
  127. module will be called cpufreq_conservative.
  128. For details, take a look at linux/Documentation/cpu-freq.
  129. If in doubt, say N.
  130. endif # CPU_FREQ