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 | ||
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 | 20 | |
1da177e4 | 21 | config CPU_FREQ_STAT |
9101be53 MF |
22 | tristate "CPU frequency translation statistics" |
23 | select CPU_FREQ_TABLE | |
24 | default y | |
25 | help | |
26 | This driver exports CPU frequency statistics information through sysfs | |
27 | file system. | |
28 | ||
29 | To compile this driver as a module, choose M here: the | |
30 | module will be called cpufreq_stats. | |
31 | ||
32 | If in doubt, say N. | |
1da177e4 LT |
33 | |
34 | config CPU_FREQ_STAT_DETAILS | |
9101be53 MF |
35 | bool "CPU frequency translation statistics details" |
36 | depends on CPU_FREQ_STAT | |
37 | help | |
38 | This will show detail CPU frequency translation table in sysfs file | |
39 | system. | |
40 | ||
41 | If in doubt, say N. | |
1da177e4 LT |
42 | |
43 | choice | |
44 | prompt "Default CPUFreq governor" | |
45 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
46 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
47 | help | |
48 | This option sets which CPUFreq governor shall be loaded at | |
49 | startup. If in doubt, select 'performance'. | |
50 | ||
51 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
52 | bool "performance" | |
53 | select CPU_FREQ_GOV_PERFORMANCE | |
54 | help | |
55 | Use the CPUFreq governor 'performance' as default. This sets | |
56 | the frequency statically to the highest frequency supported by | |
57 | the CPU. | |
58 | ||
30d221db AG |
59 | config CPU_FREQ_DEFAULT_GOV_POWERSAVE |
60 | bool "powersave" | |
6a108a14 | 61 | depends on EXPERT |
30d221db AG |
62 | select CPU_FREQ_GOV_POWERSAVE |
63 | help | |
64 | Use the CPUFreq governor 'powersave' as default. This sets | |
65 | the frequency statically to the lowest frequency supported by | |
66 | the CPU. | |
67 | ||
1da177e4 LT |
68 | config CPU_FREQ_DEFAULT_GOV_USERSPACE |
69 | bool "userspace" | |
70 | select CPU_FREQ_GOV_USERSPACE | |
71 | help | |
72 | Use the CPUFreq governor 'userspace' as default. This allows | |
0211a9c8 | 73 | you to set the CPU frequency manually or when a userspace |
1da177e4 LT |
74 | program shall be able to set the CPU dynamically without having |
75 | to enable the userspace governor manually. | |
76 | ||
1c256245 TR |
77 | config CPU_FREQ_DEFAULT_GOV_ONDEMAND |
78 | bool "ondemand" | |
79 | select CPU_FREQ_GOV_ONDEMAND | |
80 | select CPU_FREQ_GOV_PERFORMANCE | |
81 | help | |
82 | Use the CPUFreq governor 'ondemand' as default. This allows | |
83 | you to get a full dynamic frequency capable system by simply | |
84 | loading your cpufreq low-level hardware driver. | |
85 | Be aware that not all cpufreq drivers support the ondemand | |
86 | governor. If unsure have a look at the help section of the | |
87 | driver. Fallback governor will be the performance governor. | |
88 | ||
89 | config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE | |
90 | bool "conservative" | |
91 | select CPU_FREQ_GOV_CONSERVATIVE | |
92 | select CPU_FREQ_GOV_PERFORMANCE | |
93 | help | |
94 | Use the CPUFreq governor 'conservative' as default. This allows | |
95 | you to get a full dynamic frequency capable system by simply | |
96 | loading your cpufreq low-level hardware driver. | |
97 | Be aware that not all cpufreq drivers support the conservative | |
98 | governor. If unsure have a look at the help section of the | |
99 | driver. Fallback governor will be the performance governor. | |
1da177e4 LT |
100 | endchoice |
101 | ||
102 | config CPU_FREQ_GOV_PERFORMANCE | |
9101be53 MF |
103 | tristate "'performance' governor" |
104 | help | |
1da177e4 LT |
105 | This cpufreq governor sets the frequency statically to the |
106 | highest available CPU frequency. | |
107 | ||
9101be53 MF |
108 | To compile this driver as a module, choose M here: the |
109 | module will be called cpufreq_performance. | |
110 | ||
1da177e4 LT |
111 | If in doubt, say Y. |
112 | ||
113 | config CPU_FREQ_GOV_POWERSAVE | |
9101be53 MF |
114 | tristate "'powersave' governor" |
115 | help | |
1da177e4 LT |
116 | This cpufreq governor sets the frequency statically to the |
117 | lowest available CPU frequency. | |
118 | ||
9101be53 MF |
119 | To compile this driver as a module, choose M here: the |
120 | module will be called cpufreq_powersave. | |
121 | ||
1da177e4 LT |
122 | If in doubt, say Y. |
123 | ||
124 | config CPU_FREQ_GOV_USERSPACE | |
9101be53 MF |
125 | tristate "'userspace' governor for userspace frequency scaling" |
126 | help | |
1da177e4 | 127 | Enable this cpufreq governor when you either want to set the |
0211a9c8 | 128 | CPU frequency manually or when a userspace program shall |
1da177e4 | 129 | be able to set the CPU dynamically, like on LART |
4c41251e | 130 | <http://www.lartmaker.nl/>. |
1da177e4 | 131 | |
9101be53 MF |
132 | To compile this driver as a module, choose M here: the |
133 | module will be called cpufreq_userspace. | |
134 | ||
1da177e4 LT |
135 | For details, take a look at <file:Documentation/cpu-freq/>. |
136 | ||
137 | If in doubt, say Y. | |
138 | ||
139 | config CPU_FREQ_GOV_ONDEMAND | |
140 | tristate "'ondemand' cpufreq policy governor" | |
6af6e1ef | 141 | select CPU_FREQ_TABLE |
1da177e4 LT |
142 | help |
143 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
144 | The governor does a periodic polling and | |
145 | changes frequency based on the CPU utilization. | |
146 | The support for this governor depends on CPU capability to | |
147 | do fast frequency switching (i.e, very low latency frequency | |
148 | transitions). | |
149 | ||
9101be53 MF |
150 | To compile this driver as a module, choose M here: the |
151 | module will be called cpufreq_ondemand. | |
152 | ||
1da177e4 LT |
153 | For details, take a look at linux/Documentation/cpu-freq. |
154 | ||
155 | If in doubt, say N. | |
156 | ||
b9170836 DJ |
157 | config CPU_FREQ_GOV_CONSERVATIVE |
158 | tristate "'conservative' cpufreq governor" | |
159 | depends on CPU_FREQ | |
160 | help | |
161 | 'conservative' - this driver is rather similar to the 'ondemand' | |
162 | governor both in its source code and its purpose, the difference is | |
163 | its optimisation for better suitability in a battery powered | |
164 | environment. The frequency is gracefully increased and decreased | |
165 | rather than jumping to 100% when speed is required. | |
166 | ||
167 | If you have a desktop machine then you should really be considering | |
168 | the 'ondemand' governor instead, however if you are using a laptop, | |
169 | PDA or even an AMD64 based computer (due to the unacceptable | |
170 | step-by-step latency issues between the minimum and maximum frequency | |
171 | transitions in the CPU) you will probably want to use this governor. | |
172 | ||
9101be53 MF |
173 | To compile this driver as a module, choose M here: the |
174 | module will be called cpufreq_conservative. | |
175 | ||
b9170836 DJ |
176 | For details, take a look at linux/Documentation/cpu-freq. |
177 | ||
178 | If in doubt, say N. | |
179 | ||
1da177e4 | 180 | endif # CPU_FREQ |