| config CPU_FREQ | |
| bool "CPU Frequency scaling" | |
| help | |
| CPU Frequency scaling allows you to change the clock speed of | |
| CPUs on the fly. This is a nice method to save power, because | |
| the lower the CPU clock speed, the less power the CPU consumes. | |
| Note that this driver doesn't automatically change the CPU | |
| clock speed, you need to either enable a dynamic cpufreq governor | |
| (see below) after boot, or use a userspace tool. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq. | |
| For details, take a look at <file:Documentation/cpu-freq>. | |
| If in doubt, say N. | |
| if CPU_FREQ | |
| config CPU_FREQ_TABLE | |
| tristate | |
| config CPU_FREQ_DEBUG | |
| bool "Enable CPUfreq debugging" | |
| help | |
| Say Y here to enable CPUfreq subsystem (including drivers) | |
| debugging. You will need to activate it via the kernel | |
| command line by passing | |
| cpufreq.debug=<value> | |
| To get <value>, add | |
| 1 to activate CPUfreq core debugging, | |
| 2 to activate CPUfreq drivers debugging, and | |
| 4 to activate CPUfreq governor debugging | |
| config CPU_FREQ_STAT | |
| tristate "CPU frequency translation statistics" | |
| select CPU_FREQ_TABLE | |
| default y | |
| help | |
| This driver exports CPU frequency statistics information through sysfs | |
| file system. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_stats. | |
| If in doubt, say N. | |
| config CPU_FREQ_STAT_DETAILS | |
| bool "CPU frequency translation statistics details" | |
| depends on CPU_FREQ_STAT | |
| help | |
| This will show detail CPU frequency translation table in sysfs file | |
| system. | |
| If in doubt, say N. | |
| # Note that it is not currently possible to set the other governors (such as ondemand) | |
| # as the default, since if they fail to initialise, cpufreq will be | |
| # left in an undefined state. | |
| choice | |
| prompt "Default CPUFreq governor" | |
| default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
| default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
| help | |
| This option sets which CPUFreq governor shall be loaded at | |
| startup. If in doubt, select 'performance'. | |
| config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
| bool "performance" | |
| select CPU_FREQ_GOV_PERFORMANCE | |
| help | |
| Use the CPUFreq governor 'performance' as default. This sets | |
| the frequency statically to the highest frequency supported by | |
| the CPU. | |
| config CPU_FREQ_DEFAULT_GOV_USERSPACE | |
| bool "userspace" | |
| select CPU_FREQ_GOV_USERSPACE | |
| help | |
| Use the CPUFreq governor 'userspace' as default. This allows | |
| you to set the CPU frequency manually or when an userspace | |
| program shall be able to set the CPU dynamically without having | |
| to enable the userspace governor manually. | |
| endchoice | |
| config CPU_FREQ_GOV_PERFORMANCE | |
| tristate "'performance' governor" | |
| help | |
| This cpufreq governor sets the frequency statically to the | |
| highest available CPU frequency. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_performance. | |
| If in doubt, say Y. | |
| config CPU_FREQ_GOV_POWERSAVE | |
| tristate "'powersave' governor" | |
| help | |
| This cpufreq governor sets the frequency statically to the | |
| lowest available CPU frequency. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_powersave. | |
| If in doubt, say Y. | |
| config CPU_FREQ_GOV_USERSPACE | |
| tristate "'userspace' governor for userspace frequency scaling" | |
| help | |
| Enable this cpufreq governor when you either want to set the | |
| CPU frequency manually or when an userspace program shall | |
| be able to set the CPU dynamically, like on LART | |
| <http://www.lartmaker.nl/>. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_userspace. | |
| For details, take a look at <file:Documentation/cpu-freq/>. | |
| If in doubt, say Y. | |
| config CPU_FREQ_GOV_ONDEMAND | |
| tristate "'ondemand' cpufreq policy governor" | |
| select CPU_FREQ_TABLE | |
| help | |
| 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
| The governor does a periodic polling and | |
| changes frequency based on the CPU utilization. | |
| The support for this governor depends on CPU capability to | |
| do fast frequency switching (i.e, very low latency frequency | |
| transitions). | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_ondemand. | |
| For details, take a look at linux/Documentation/cpu-freq. | |
| If in doubt, say N. | |
| config CPU_FREQ_GOV_CONSERVATIVE | |
| tristate "'conservative' cpufreq governor" | |
| depends on CPU_FREQ | |
| help | |
| 'conservative' - this driver is rather similar to the 'ondemand' | |
| governor both in its source code and its purpose, the difference is | |
| its optimisation for better suitability in a battery powered | |
| environment. The frequency is gracefully increased and decreased | |
| rather than jumping to 100% when speed is required. | |
| If you have a desktop machine then you should really be considering | |
| the 'ondemand' governor instead, however if you are using a laptop, | |
| PDA or even an AMD64 based computer (due to the unacceptable | |
| step-by-step latency issues between the minimum and maximum frequency | |
| transitions in the CPU) you will probably want to use this governor. | |
| To compile this driver as a module, choose M here: the | |
| module will be called cpufreq_conservative. | |
| For details, take a look at linux/Documentation/cpu-freq. | |
| If in doubt, say N. | |
| endif # CPU_FREQ |