| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | 
| Adrian Bunk | f0ec313 | 2007-02-05 16:12:45 -0800 | [diff] [blame] | 19 | tristate | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |  | 
| Dave Jones | 3310010 | 2005-05-31 19:03:44 -0700 | [diff] [blame] | 49 | # Note that it is not currently possible to set the other governors (such as ondemand) | 
|  | 50 | # as the default, since if they fail to initialise, cpufreq will be | 
|  | 51 | # left in an undefined state. | 
|  | 52 |  | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | choice | 
|  | 54 | prompt "Default CPUFreq governor" | 
|  | 55 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | 
|  | 56 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | 
|  | 57 | help | 
|  | 58 | This option sets which CPUFreq governor shall be loaded at | 
|  | 59 | startup. If in doubt, select 'performance'. | 
|  | 60 |  | 
|  | 61 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | 
|  | 62 | bool "performance" | 
|  | 63 | select CPU_FREQ_GOV_PERFORMANCE | 
|  | 64 | help | 
|  | 65 | Use the CPUFreq governor 'performance' as default. This sets | 
|  | 66 | the frequency statically to the highest frequency supported by | 
|  | 67 | the CPU. | 
|  | 68 |  | 
|  | 69 | config CPU_FREQ_DEFAULT_GOV_USERSPACE | 
|  | 70 | bool "userspace" | 
|  | 71 | select CPU_FREQ_GOV_USERSPACE | 
|  | 72 | help | 
|  | 73 | Use the CPUFreq governor 'userspace' as default. This allows | 
|  | 74 | you to set the CPU frequency manually or when an userspace | 
|  | 75 | program shall be able to set the CPU dynamically without having | 
|  | 76 | to enable the userspace governor manually. | 
|  | 77 |  | 
|  | 78 | endchoice | 
|  | 79 |  | 
|  | 80 | config CPU_FREQ_GOV_PERFORMANCE | 
|  | 81 | tristate "'performance' governor" | 
|  | 82 | help | 
|  | 83 | This cpufreq governor sets the frequency statically to the | 
|  | 84 | highest available CPU frequency. | 
|  | 85 |  | 
|  | 86 | If in doubt, say Y. | 
|  | 87 |  | 
|  | 88 | config CPU_FREQ_GOV_POWERSAVE | 
|  | 89 | tristate "'powersave' governor" | 
|  | 90 | help | 
|  | 91 | This cpufreq governor sets the frequency statically to the | 
|  | 92 | lowest available CPU frequency. | 
|  | 93 |  | 
|  | 94 | If in doubt, say Y. | 
|  | 95 |  | 
|  | 96 | config CPU_FREQ_GOV_USERSPACE | 
|  | 97 | tristate "'userspace' governor for userspace frequency scaling" | 
|  | 98 | help | 
|  | 99 | Enable this cpufreq governor when you either want to set the | 
|  | 100 | CPU frequency manually or when an userspace program shall | 
|  | 101 | be able to set the CPU dynamically, like on LART | 
| Erik Mouw | 4c41251 | 2006-04-03 14:21:00 +0200 | [diff] [blame] | 102 | <http://www.lartmaker.nl/>. | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 |  | 
|  | 104 | For details, take a look at <file:Documentation/cpu-freq/>. | 
|  | 105 |  | 
|  | 106 | If in doubt, say Y. | 
|  | 107 |  | 
|  | 108 | config CPU_FREQ_GOV_ONDEMAND | 
|  | 109 | tristate "'ondemand' cpufreq policy governor" | 
| Dave Jones | 6af6e1e | 2006-11-21 16:58:59 -0500 | [diff] [blame] | 110 | select CPU_FREQ_TABLE | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | help | 
|  | 112 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | 
|  | 113 | The governor does a periodic polling and | 
|  | 114 | changes frequency based on the CPU utilization. | 
|  | 115 | The support for this governor depends on CPU capability to | 
|  | 116 | do fast frequency switching (i.e, very low latency frequency | 
|  | 117 | transitions). | 
|  | 118 |  | 
|  | 119 | For details, take a look at linux/Documentation/cpu-freq. | 
|  | 120 |  | 
|  | 121 | If in doubt, say N. | 
|  | 122 |  | 
| Dave Jones | b917083 | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 123 | config CPU_FREQ_GOV_CONSERVATIVE | 
|  | 124 | tristate "'conservative' cpufreq governor" | 
|  | 125 | depends on CPU_FREQ | 
|  | 126 | help | 
|  | 127 | 'conservative' - this driver is rather similar to the 'ondemand' | 
|  | 128 | governor both in its source code and its purpose, the difference is | 
|  | 129 | its optimisation for better suitability in a battery powered | 
|  | 130 | environment.  The frequency is gracefully increased and decreased | 
|  | 131 | rather than jumping to 100% when speed is required. | 
|  | 132 |  | 
|  | 133 | If you have a desktop machine then you should really be considering | 
|  | 134 | the 'ondemand' governor instead, however if you are using a laptop, | 
|  | 135 | PDA or even an AMD64 based computer (due to the unacceptable | 
|  | 136 | step-by-step latency issues between the minimum and maximum frequency | 
|  | 137 | transitions in the CPU) you will probably want to use this governor. | 
|  | 138 |  | 
|  | 139 | For details, take a look at linux/Documentation/cpu-freq. | 
|  | 140 |  | 
|  | 141 | If in doubt, say N. | 
|  | 142 |  | 
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | endif	# CPU_FREQ |