Kconfig 6.0 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. 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. config 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. config CPU_FREQ_DEFAULT_GOV_USERSPACE
  60. bool "userspace"
  61. select CPU_FREQ_GOV_USERSPACE
  62. help
  63. Use the CPUFreq governor 'userspace' as default. This allows
  64. you to set the CPU frequency manually or when an userspace
  65. program shall be able to set the CPU dynamically without having
  66. to enable the userspace governor manually.
  67. config CPU_FREQ_DEFAULT_GOV_ONDEMAND
  68. bool "ondemand"
  69. select CPU_FREQ_GOV_ONDEMAND
  70. select CPU_FREQ_GOV_PERFORMANCE
  71. help
  72. Use the CPUFreq governor 'ondemand' as default. This allows
  73. you to get a full dynamic frequency capable system by simply
  74. loading your cpufreq low-level hardware driver.
  75. Be aware that not all cpufreq drivers support the ondemand
  76. governor. If unsure have a look at the help section of the
  77. driver. Fallback governor will be the performance governor.
  78. config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
  79. bool "conservative"
  80. select CPU_FREQ_GOV_CONSERVATIVE
  81. select CPU_FREQ_GOV_PERFORMANCE
  82. help
  83. Use the CPUFreq governor 'conservative' 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 conservative
  87. governor. If unsure have a look at the help section of the
  88. driver. Fallback governor will be the performance governor.
  89. endchoice
  90. config CPU_FREQ_GOV_PERFORMANCE
  91. tristate "'performance' governor"
  92. help
  93. This cpufreq governor sets the frequency statically to the
  94. highest available CPU frequency.
  95. To compile this driver as a module, choose M here: the
  96. module will be called cpufreq_performance.
  97. If in doubt, say Y.
  98. config CPU_FREQ_GOV_POWERSAVE
  99. tristate "'powersave' governor"
  100. help
  101. This cpufreq governor sets the frequency statically to the
  102. lowest available CPU frequency.
  103. To compile this driver as a module, choose M here: the
  104. module will be called cpufreq_powersave.
  105. If in doubt, say Y.
  106. config CPU_FREQ_GOV_USERSPACE
  107. tristate "'userspace' governor for userspace frequency scaling"
  108. help
  109. Enable this cpufreq governor when you either want to set the
  110. CPU frequency manually or when an userspace program shall
  111. be able to set the CPU dynamically, like on LART
  112. <http://www.lartmaker.nl/>.
  113. To compile this driver as a module, choose M here: the
  114. module will be called cpufreq_userspace.
  115. For details, take a look at <file:Documentation/cpu-freq/>.
  116. If in doubt, say Y.
  117. config CPU_FREQ_GOV_ONDEMAND
  118. tristate "'ondemand' cpufreq policy governor"
  119. select CPU_FREQ_TABLE
  120. help
  121. 'ondemand' - This driver adds a dynamic cpufreq policy governor.
  122. The governor does a periodic polling and
  123. changes frequency based on the CPU utilization.
  124. The support for this governor depends on CPU capability to
  125. do fast frequency switching (i.e, very low latency frequency
  126. transitions).
  127. To compile this driver as a module, choose M here: the
  128. module will be called cpufreq_ondemand.
  129. For details, take a look at linux/Documentation/cpu-freq.
  130. If in doubt, say N.
  131. config CPU_FREQ_GOV_CONSERVATIVE
  132. tristate "'conservative' cpufreq governor"
  133. depends on CPU_FREQ
  134. help
  135. 'conservative' - this driver is rather similar to the 'ondemand'
  136. governor both in its source code and its purpose, the difference is
  137. its optimisation for better suitability in a battery powered
  138. environment. The frequency is gracefully increased and decreased
  139. rather than jumping to 100% when speed is required.
  140. If you have a desktop machine then you should really be considering
  141. the 'ondemand' governor instead, however if you are using a laptop,
  142. PDA or even an AMD64 based computer (due to the unacceptable
  143. step-by-step latency issues between the minimum and maximum frequency
  144. transitions in the CPU) you will probably want to use this governor.
  145. To compile this driver as a module, choose M here: the
  146. module will be called cpufreq_conservative.
  147. For details, take a look at linux/Documentation/cpu-freq.
  148. If in doubt, say N.
  149. endif # CPU_FREQ