Commit | Line | Data |
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1da177e4 LT |
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 | ||
9101be53 MF |
12 | To compile this driver as a module, choose M here: the |
13 | module will be called cpufreq. | |
14 | ||
1da177e4 LT |
15 | For details, take a look at <file:Documentation/cpu-freq>. |
16 | ||
17 | If in doubt, say N. | |
18 | ||
19 | if CPU_FREQ | |
20 | ||
21 | config CPU_FREQ_TABLE | |
9101be53 | 22 | tristate |
1da177e4 LT |
23 | |
24 | config CPU_FREQ_DEBUG | |
25 | bool "Enable CPUfreq debugging" | |
26 | help | |
27 | Say Y here to enable CPUfreq subsystem (including drivers) | |
28 | debugging. You will need to activate it via the kernel | |
29 | command line by passing | |
30 | cpufreq.debug=<value> | |
31 | ||
32 | To get <value>, add | |
33 | 1 to activate CPUfreq core debugging, | |
34 | 2 to activate CPUfreq drivers debugging, and | |
35 | 4 to activate CPUfreq governor debugging | |
36 | ||
37 | config CPU_FREQ_STAT | |
9101be53 MF |
38 | tristate "CPU frequency translation statistics" |
39 | select CPU_FREQ_TABLE | |
40 | default y | |
41 | help | |
42 | This driver exports CPU frequency statistics information through sysfs | |
43 | file system. | |
44 | ||
45 | To compile this driver as a module, choose M here: the | |
46 | module will be called cpufreq_stats. | |
47 | ||
48 | If in doubt, say N. | |
1da177e4 LT |
49 | |
50 | config CPU_FREQ_STAT_DETAILS | |
9101be53 MF |
51 | bool "CPU frequency translation statistics details" |
52 | depends on CPU_FREQ_STAT | |
53 | help | |
54 | This will show detail CPU frequency translation table in sysfs file | |
55 | system. | |
56 | ||
57 | If in doubt, say N. | |
1da177e4 | 58 | |
33100108 DJ |
59 | # Note that it is not currently possible to set the other governors (such as ondemand) |
60 | # as the default, since if they fail to initialise, cpufreq will be | |
61 | # left in an undefined state. | |
62 | ||
1da177e4 LT |
63 | choice |
64 | prompt "Default CPUFreq governor" | |
65 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
66 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
67 | help | |
68 | This option sets which CPUFreq governor shall be loaded at | |
69 | startup. If in doubt, select 'performance'. | |
70 | ||
71 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
72 | bool "performance" | |
73 | select CPU_FREQ_GOV_PERFORMANCE | |
74 | help | |
75 | Use the CPUFreq governor 'performance' as default. This sets | |
76 | the frequency statically to the highest frequency supported by | |
77 | the CPU. | |
78 | ||
79 | config CPU_FREQ_DEFAULT_GOV_USERSPACE | |
80 | bool "userspace" | |
81 | select CPU_FREQ_GOV_USERSPACE | |
82 | help | |
83 | Use the CPUFreq governor 'userspace' as default. This allows | |
84 | you to set the CPU frequency manually or when an userspace | |
85 | program shall be able to set the CPU dynamically without having | |
86 | to enable the userspace governor manually. | |
87 | ||
88 | endchoice | |
89 | ||
90 | config CPU_FREQ_GOV_PERFORMANCE | |
9101be53 MF |
91 | tristate "'performance' governor" |
92 | help | |
1da177e4 LT |
93 | This cpufreq governor sets the frequency statically to the |
94 | highest available CPU frequency. | |
95 | ||
9101be53 MF |
96 | To compile this driver as a module, choose M here: the |
97 | module will be called cpufreq_performance. | |
98 | ||
1da177e4 LT |
99 | If in doubt, say Y. |
100 | ||
101 | config CPU_FREQ_GOV_POWERSAVE | |
9101be53 MF |
102 | tristate "'powersave' governor" |
103 | help | |
1da177e4 LT |
104 | This cpufreq governor sets the frequency statically to the |
105 | lowest available CPU frequency. | |
106 | ||
9101be53 MF |
107 | To compile this driver as a module, choose M here: the |
108 | module will be called cpufreq_powersave. | |
109 | ||
1da177e4 LT |
110 | If in doubt, say Y. |
111 | ||
112 | config CPU_FREQ_GOV_USERSPACE | |
9101be53 MF |
113 | tristate "'userspace' governor for userspace frequency scaling" |
114 | help | |
1da177e4 LT |
115 | Enable this cpufreq governor when you either want to set the |
116 | CPU frequency manually or when an userspace program shall | |
117 | be able to set the CPU dynamically, like on LART | |
4c41251e | 118 | <http://www.lartmaker.nl/>. |
1da177e4 | 119 | |
9101be53 MF |
120 | To compile this driver as a module, choose M here: the |
121 | module will be called cpufreq_userspace. | |
122 | ||
1da177e4 LT |
123 | For details, take a look at <file:Documentation/cpu-freq/>. |
124 | ||
125 | If in doubt, say Y. | |
126 | ||
127 | config CPU_FREQ_GOV_ONDEMAND | |
128 | tristate "'ondemand' cpufreq policy governor" | |
6af6e1ef | 129 | select CPU_FREQ_TABLE |
1da177e4 LT |
130 | help |
131 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
132 | The governor does a periodic polling and | |
133 | changes frequency based on the CPU utilization. | |
134 | The support for this governor depends on CPU capability to | |
135 | do fast frequency switching (i.e, very low latency frequency | |
136 | transitions). | |
137 | ||
9101be53 MF |
138 | To compile this driver as a module, choose M here: the |
139 | module will be called cpufreq_ondemand. | |
140 | ||
1da177e4 LT |
141 | For details, take a look at linux/Documentation/cpu-freq. |
142 | ||
143 | If in doubt, say N. | |
144 | ||
b9170836 DJ |
145 | config CPU_FREQ_GOV_CONSERVATIVE |
146 | tristate "'conservative' cpufreq governor" | |
147 | depends on CPU_FREQ | |
148 | help | |
149 | 'conservative' - this driver is rather similar to the 'ondemand' | |
150 | governor both in its source code and its purpose, the difference is | |
151 | its optimisation for better suitability in a battery powered | |
152 | environment. The frequency is gracefully increased and decreased | |
153 | rather than jumping to 100% when speed is required. | |
154 | ||
155 | If you have a desktop machine then you should really be considering | |
156 | the 'ondemand' governor instead, however if you are using a laptop, | |
157 | PDA or even an AMD64 based computer (due to the unacceptable | |
158 | step-by-step latency issues between the minimum and maximum frequency | |
159 | transitions in the CPU) you will probably want to use this governor. | |
160 | ||
9101be53 MF |
161 | To compile this driver as a module, choose M here: the |
162 | module will be called cpufreq_conservative. | |
163 | ||
b9170836 DJ |
164 | For details, take a look at linux/Documentation/cpu-freq. |
165 | ||
166 | If in doubt, say N. | |
167 | ||
1da177e4 | 168 | endif # CPU_FREQ |