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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 | ||
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 | |
9101be53 | 19 | tristate |
1da177e4 LT |
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 | |
9101be53 MF |
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 | To compile this driver as a module, choose M here: the | |
43 | module will be called cpufreq_stats. | |
44 | ||
45 | If in doubt, say N. | |
1da177e4 LT |
46 | |
47 | config CPU_FREQ_STAT_DETAILS | |
9101be53 MF |
48 | bool "CPU frequency translation statistics details" |
49 | depends on CPU_FREQ_STAT | |
50 | help | |
51 | This will show detail CPU frequency translation table in sysfs file | |
52 | system. | |
53 | ||
54 | If in doubt, say N. | |
1da177e4 LT |
55 | |
56 | choice | |
57 | prompt "Default CPUFreq governor" | |
58 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
59 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
60 | help | |
61 | This option sets which CPUFreq governor shall be loaded at | |
62 | startup. If in doubt, select 'performance'. | |
63 | ||
64 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
65 | bool "performance" | |
66 | select CPU_FREQ_GOV_PERFORMANCE | |
67 | help | |
68 | Use the CPUFreq governor 'performance' as default. This sets | |
69 | the frequency statically to the highest frequency supported by | |
70 | the CPU. | |
71 | ||
72 | config CPU_FREQ_DEFAULT_GOV_USERSPACE | |
73 | bool "userspace" | |
74 | select CPU_FREQ_GOV_USERSPACE | |
75 | help | |
76 | Use the CPUFreq governor 'userspace' as default. This allows | |
77 | you to set the CPU frequency manually or when an userspace | |
78 | program shall be able to set the CPU dynamically without having | |
79 | to enable the userspace governor manually. | |
80 | ||
1c256245 TR |
81 | config CPU_FREQ_DEFAULT_GOV_ONDEMAND |
82 | bool "ondemand" | |
83 | select CPU_FREQ_GOV_ONDEMAND | |
84 | select CPU_FREQ_GOV_PERFORMANCE | |
85 | help | |
86 | Use the CPUFreq governor 'ondemand' as default. This allows | |
87 | you to get a full dynamic frequency capable system by simply | |
88 | loading your cpufreq low-level hardware driver. | |
89 | Be aware that not all cpufreq drivers support the ondemand | |
90 | governor. If unsure have a look at the help section of the | |
91 | driver. Fallback governor will be the performance governor. | |
92 | ||
93 | config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE | |
94 | bool "conservative" | |
95 | select CPU_FREQ_GOV_CONSERVATIVE | |
96 | select CPU_FREQ_GOV_PERFORMANCE | |
97 | help | |
98 | Use the CPUFreq governor 'conservative' as default. This allows | |
99 | you to get a full dynamic frequency capable system by simply | |
100 | loading your cpufreq low-level hardware driver. | |
101 | Be aware that not all cpufreq drivers support the conservative | |
102 | governor. If unsure have a look at the help section of the | |
103 | driver. Fallback governor will be the performance governor. | |
1da177e4 LT |
104 | endchoice |
105 | ||
106 | config CPU_FREQ_GOV_PERFORMANCE | |
9101be53 MF |
107 | tristate "'performance' governor" |
108 | help | |
1da177e4 LT |
109 | This cpufreq governor sets the frequency statically to the |
110 | highest available CPU frequency. | |
111 | ||
9101be53 MF |
112 | To compile this driver as a module, choose M here: the |
113 | module will be called cpufreq_performance. | |
114 | ||
1da177e4 LT |
115 | If in doubt, say Y. |
116 | ||
117 | config CPU_FREQ_GOV_POWERSAVE | |
9101be53 MF |
118 | tristate "'powersave' governor" |
119 | help | |
1da177e4 LT |
120 | This cpufreq governor sets the frequency statically to the |
121 | lowest available CPU frequency. | |
122 | ||
9101be53 MF |
123 | To compile this driver as a module, choose M here: the |
124 | module will be called cpufreq_powersave. | |
125 | ||
1da177e4 LT |
126 | If in doubt, say Y. |
127 | ||
128 | config CPU_FREQ_GOV_USERSPACE | |
9101be53 MF |
129 | tristate "'userspace' governor for userspace frequency scaling" |
130 | help | |
1da177e4 LT |
131 | Enable this cpufreq governor when you either want to set the |
132 | CPU frequency manually or when an userspace program shall | |
133 | be able to set the CPU dynamically, like on LART | |
4c41251e | 134 | <http://www.lartmaker.nl/>. |
1da177e4 | 135 | |
9101be53 MF |
136 | To compile this driver as a module, choose M here: the |
137 | module will be called cpufreq_userspace. | |
138 | ||
1da177e4 LT |
139 | For details, take a look at <file:Documentation/cpu-freq/>. |
140 | ||
141 | If in doubt, say Y. | |
142 | ||
143 | config CPU_FREQ_GOV_ONDEMAND | |
144 | tristate "'ondemand' cpufreq policy governor" | |
6af6e1ef | 145 | select CPU_FREQ_TABLE |
1da177e4 LT |
146 | help |
147 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
148 | The governor does a periodic polling and | |
149 | changes frequency based on the CPU utilization. | |
150 | The support for this governor depends on CPU capability to | |
151 | do fast frequency switching (i.e, very low latency frequency | |
152 | transitions). | |
153 | ||
9101be53 MF |
154 | To compile this driver as a module, choose M here: the |
155 | module will be called cpufreq_ondemand. | |
156 | ||
1da177e4 LT |
157 | For details, take a look at linux/Documentation/cpu-freq. |
158 | ||
159 | If in doubt, say N. | |
160 | ||
b9170836 DJ |
161 | config CPU_FREQ_GOV_CONSERVATIVE |
162 | tristate "'conservative' cpufreq governor" | |
163 | depends on CPU_FREQ | |
164 | help | |
165 | 'conservative' - this driver is rather similar to the 'ondemand' | |
166 | governor both in its source code and its purpose, the difference is | |
167 | its optimisation for better suitability in a battery powered | |
168 | environment. The frequency is gracefully increased and decreased | |
169 | rather than jumping to 100% when speed is required. | |
170 | ||
171 | If you have a desktop machine then you should really be considering | |
172 | the 'ondemand' governor instead, however if you are using a laptop, | |
173 | PDA or even an AMD64 based computer (due to the unacceptable | |
174 | step-by-step latency issues between the minimum and maximum frequency | |
175 | transitions in the CPU) you will probably want to use this governor. | |
176 | ||
9101be53 MF |
177 | To compile this driver as a module, choose M here: the |
178 | module will be called cpufreq_conservative. | |
179 | ||
b9170836 DJ |
180 | For details, take a look at linux/Documentation/cpu-freq. |
181 | ||
182 | If in doubt, say N. | |
183 | ||
1da177e4 | 184 | endif # CPU_FREQ |