| 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 |
| 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 |