Kconfig 6.1 KB

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  1. menu "CPU Frequency scaling"
  2. config CPU_FREQ
  3. bool "CPU Frequency scaling"
  4. help
  5. CPU Frequency scaling allows you to change the clock speed of
  6. CPUs on the fly. This is a nice method to save power, because
  7. the lower the CPU clock speed, the less power the CPU consumes.
  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. For details, take a look at <file:Documentation/cpu-freq>.
  12. If in doubt, say N.
  13. if CPU_FREQ
  14. config CPU_FREQ_TABLE
  15. tristate
  16. config CPU_FREQ_STAT
  17. tristate "CPU frequency translation statistics"
  18. select CPU_FREQ_TABLE
  19. default y
  20. help
  21. This driver exports CPU frequency statistics information through sysfs
  22. file system.
  23. To compile this driver as a module, choose M here: the
  24. module will be called cpufreq_stats.
  25. If in doubt, say N.
  26. config CPU_FREQ_STAT_DETAILS
  27. bool "CPU frequency translation statistics details"
  28. depends on CPU_FREQ_STAT
  29. help
  30. This will show detail CPU frequency translation table in sysfs file
  31. system.
  32. If in doubt, say N.
  33. choice
  34. prompt "Default CPUFreq governor"
  35. default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
  36. default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  37. help
  38. This option sets which CPUFreq governor shall be loaded at
  39. startup. If in doubt, select 'performance'.
  40. config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
  41. bool "performance"
  42. select CPU_FREQ_GOV_PERFORMANCE
  43. help
  44. Use the CPUFreq governor 'performance' as default. This sets
  45. the frequency statically to the highest frequency supported by
  46. the CPU.
  47. config CPU_FREQ_DEFAULT_GOV_POWERSAVE
  48. bool "powersave"
  49. depends on EXPERT
  50. select CPU_FREQ_GOV_POWERSAVE
  51. help
  52. Use the CPUFreq governor 'powersave' as default. This sets
  53. the frequency statically to the lowest frequency supported by
  54. the CPU.
  55. config CPU_FREQ_DEFAULT_GOV_USERSPACE
  56. bool "userspace"
  57. select CPU_FREQ_GOV_USERSPACE
  58. help
  59. Use the CPUFreq governor 'userspace' as default. This allows
  60. you to set the CPU frequency manually or when a userspace
  61. program shall be able to set the CPU dynamically without having
  62. to enable the userspace governor manually.
  63. config CPU_FREQ_DEFAULT_GOV_ONDEMAND
  64. bool "ondemand"
  65. select CPU_FREQ_GOV_ONDEMAND
  66. select CPU_FREQ_GOV_PERFORMANCE
  67. help
  68. Use the CPUFreq governor 'ondemand' as default. This allows
  69. you to get a full dynamic frequency capable system by simply
  70. loading your cpufreq low-level hardware driver.
  71. Be aware that not all cpufreq drivers support the ondemand
  72. governor. If unsure have a look at the help section of the
  73. driver. Fallback governor will be the performance governor.
  74. config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
  75. bool "conservative"
  76. select CPU_FREQ_GOV_CONSERVATIVE
  77. select CPU_FREQ_GOV_PERFORMANCE
  78. help
  79. Use the CPUFreq governor 'conservative' as default. This allows
  80. you to get a full dynamic frequency capable system by simply
  81. loading your cpufreq low-level hardware driver.
  82. Be aware that not all cpufreq drivers support the conservative
  83. governor. If unsure have a look at the help section of the
  84. driver. Fallback governor will be the performance governor.
  85. endchoice
  86. config CPU_FREQ_GOV_PERFORMANCE
  87. tristate "'performance' governor"
  88. help
  89. This cpufreq governor sets the frequency statically to the
  90. highest available CPU frequency.
  91. To compile this driver as a module, choose M here: the
  92. module will be called cpufreq_performance.
  93. If in doubt, say Y.
  94. config CPU_FREQ_GOV_POWERSAVE
  95. tristate "'powersave' governor"
  96. help
  97. This cpufreq governor sets the frequency statically to the
  98. lowest available CPU frequency.
  99. To compile this driver as a module, choose M here: the
  100. module will be called cpufreq_powersave.
  101. If in doubt, say Y.
  102. config CPU_FREQ_GOV_USERSPACE
  103. tristate "'userspace' governor for userspace frequency scaling"
  104. help
  105. Enable this cpufreq governor when you either want to set the
  106. CPU frequency manually or when a userspace program shall
  107. be able to set the CPU dynamically, like on LART
  108. <http://www.lartmaker.nl/>.
  109. To compile this driver as a module, choose M here: the
  110. module will be called cpufreq_userspace.
  111. For details, take a look at <file:Documentation/cpu-freq/>.
  112. If in doubt, say Y.
  113. config CPU_FREQ_GOV_ONDEMAND
  114. tristate "'ondemand' cpufreq policy governor"
  115. select CPU_FREQ_TABLE
  116. help
  117. 'ondemand' - This driver adds a dynamic cpufreq policy governor.
  118. The governor does a periodic polling and
  119. changes frequency based on the CPU utilization.
  120. The support for this governor depends on CPU capability to
  121. do fast frequency switching (i.e, very low latency frequency
  122. transitions).
  123. To compile this driver as a module, choose M here: the
  124. module will be called cpufreq_ondemand.
  125. For details, take a look at linux/Documentation/cpu-freq.
  126. If in doubt, say N.
  127. config CPU_FREQ_GOV_CONSERVATIVE
  128. tristate "'conservative' cpufreq governor"
  129. depends on CPU_FREQ
  130. help
  131. 'conservative' - this driver is rather similar to the 'ondemand'
  132. governor both in its source code and its purpose, the difference is
  133. its optimisation for better suitability in a battery powered
  134. environment. The frequency is gracefully increased and decreased
  135. rather than jumping to 100% when speed is required.
  136. If you have a desktop machine then you should really be considering
  137. the 'ondemand' governor instead, however if you are using a laptop,
  138. PDA or even an AMD64 based computer (due to the unacceptable
  139. step-by-step latency issues between the minimum and maximum frequency
  140. transitions in the CPU) you will probably want to use this governor.
  141. To compile this driver as a module, choose M here: the
  142. module will be called cpufreq_conservative.
  143. For details, take a look at linux/Documentation/cpu-freq.
  144. If in doubt, say N.
  145. menu "x86 CPU frequency scaling drivers"
  146. depends on X86
  147. source "drivers/cpufreq/Kconfig.x86"
  148. endmenu
  149. menu "ARM CPU frequency scaling drivers"
  150. depends on ARM
  151. source "drivers/cpufreq/Kconfig.arm"
  152. endmenu
  153. menu "PowerPC CPU frequency scaling drivers"
  154. depends on PPC32 || PPC64
  155. source "drivers/cpufreq/Kconfig.powerpc"
  156. endmenu
  157. endif
  158. endmenu