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bb0a56ec DJ |
1 | menu "CPU Frequency scaling" |
2 | ||
1da177e4 LT |
3 | config CPU_FREQ |
4 | bool "CPU Frequency scaling" | |
5 | help | |
6 | CPU Frequency scaling allows you to change the clock speed of | |
7 | CPUs on the fly. This is a nice method to save power, because | |
8 | the lower the CPU clock speed, the less power the CPU consumes. | |
9 | ||
10 | Note that this driver doesn't automatically change the CPU | |
11 | clock speed, you need to either enable a dynamic cpufreq governor | |
12 | (see below) after boot, or use a userspace tool. | |
13 | ||
14 | For details, take a look at <file:Documentation/cpu-freq>. | |
15 | ||
16 | If in doubt, say N. | |
17 | ||
18 | if CPU_FREQ | |
19 | ||
20 | config CPU_FREQ_TABLE | |
9101be53 | 21 | tristate |
1da177e4 | 22 | |
1da177e4 | 23 | config CPU_FREQ_STAT |
9101be53 MF |
24 | tristate "CPU frequency translation statistics" |
25 | select CPU_FREQ_TABLE | |
26 | default y | |
27 | help | |
28 | This driver exports CPU frequency statistics information through sysfs | |
29 | file system. | |
30 | ||
31 | To compile this driver as a module, choose M here: the | |
32 | module will be called cpufreq_stats. | |
33 | ||
34 | If in doubt, say N. | |
1da177e4 LT |
35 | |
36 | config CPU_FREQ_STAT_DETAILS | |
9101be53 MF |
37 | bool "CPU frequency translation statistics details" |
38 | depends on CPU_FREQ_STAT | |
39 | help | |
40 | This will show detail CPU frequency translation table in sysfs file | |
41 | system. | |
42 | ||
43 | If in doubt, say N. | |
1da177e4 LT |
44 | |
45 | choice | |
46 | prompt "Default CPUFreq governor" | |
47 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
48 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
49 | help | |
50 | This option sets which CPUFreq governor shall be loaded at | |
51 | startup. If in doubt, select 'performance'. | |
52 | ||
53 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
54 | bool "performance" | |
55 | select CPU_FREQ_GOV_PERFORMANCE | |
56 | help | |
57 | Use the CPUFreq governor 'performance' as default. This sets | |
58 | the frequency statically to the highest frequency supported by | |
59 | the CPU. | |
60 | ||
30d221db AG |
61 | config CPU_FREQ_DEFAULT_GOV_POWERSAVE |
62 | bool "powersave" | |
6a108a14 | 63 | depends on EXPERT |
30d221db AG |
64 | select CPU_FREQ_GOV_POWERSAVE |
65 | help | |
66 | Use the CPUFreq governor 'powersave' as default. This sets | |
67 | the frequency statically to the lowest frequency supported by | |
68 | the CPU. | |
69 | ||
1da177e4 LT |
70 | config CPU_FREQ_DEFAULT_GOV_USERSPACE |
71 | bool "userspace" | |
72 | select CPU_FREQ_GOV_USERSPACE | |
73 | help | |
74 | Use the CPUFreq governor 'userspace' as default. This allows | |
0211a9c8 | 75 | you to set the CPU frequency manually or when a userspace |
1da177e4 LT |
76 | program shall be able to set the CPU dynamically without having |
77 | to enable the userspace governor manually. | |
78 | ||
1c256245 TR |
79 | config CPU_FREQ_DEFAULT_GOV_ONDEMAND |
80 | bool "ondemand" | |
81 | select CPU_FREQ_GOV_ONDEMAND | |
82 | select CPU_FREQ_GOV_PERFORMANCE | |
83 | help | |
84 | Use the CPUFreq governor 'ondemand' as default. This allows | |
85 | you to get a full dynamic frequency capable system by simply | |
86 | loading your cpufreq low-level hardware driver. | |
87 | Be aware that not all cpufreq drivers support the ondemand | |
88 | governor. If unsure have a look at the help section of the | |
89 | driver. Fallback governor will be the performance governor. | |
90 | ||
91 | config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE | |
92 | bool "conservative" | |
93 | select CPU_FREQ_GOV_CONSERVATIVE | |
94 | select CPU_FREQ_GOV_PERFORMANCE | |
95 | help | |
96 | Use the CPUFreq governor 'conservative' as default. This allows | |
97 | you to get a full dynamic frequency capable system by simply | |
98 | loading your cpufreq low-level hardware driver. | |
99 | Be aware that not all cpufreq drivers support the conservative | |
100 | governor. If unsure have a look at the help section of the | |
101 | driver. Fallback governor will be the performance governor. | |
1da177e4 LT |
102 | endchoice |
103 | ||
104 | config CPU_FREQ_GOV_PERFORMANCE | |
9101be53 MF |
105 | tristate "'performance' governor" |
106 | help | |
1da177e4 LT |
107 | This cpufreq governor sets the frequency statically to the |
108 | highest available CPU frequency. | |
109 | ||
9101be53 MF |
110 | To compile this driver as a module, choose M here: the |
111 | module will be called cpufreq_performance. | |
112 | ||
1da177e4 LT |
113 | If in doubt, say Y. |
114 | ||
115 | config CPU_FREQ_GOV_POWERSAVE | |
9101be53 MF |
116 | tristate "'powersave' governor" |
117 | help | |
1da177e4 LT |
118 | This cpufreq governor sets the frequency statically to the |
119 | lowest available CPU frequency. | |
120 | ||
9101be53 MF |
121 | To compile this driver as a module, choose M here: the |
122 | module will be called cpufreq_powersave. | |
123 | ||
1da177e4 LT |
124 | If in doubt, say Y. |
125 | ||
126 | config CPU_FREQ_GOV_USERSPACE | |
9101be53 MF |
127 | tristate "'userspace' governor for userspace frequency scaling" |
128 | help | |
1da177e4 | 129 | Enable this cpufreq governor when you either want to set the |
0211a9c8 | 130 | CPU frequency manually or when a userspace program shall |
1da177e4 | 131 | be able to set the CPU dynamically, like on LART |
4c41251e | 132 | <http://www.lartmaker.nl/>. |
1da177e4 | 133 | |
9101be53 MF |
134 | To compile this driver as a module, choose M here: the |
135 | module will be called cpufreq_userspace. | |
136 | ||
1da177e4 LT |
137 | For details, take a look at <file:Documentation/cpu-freq/>. |
138 | ||
139 | If in doubt, say Y. | |
140 | ||
141 | config CPU_FREQ_GOV_ONDEMAND | |
142 | tristate "'ondemand' cpufreq policy governor" | |
6af6e1ef | 143 | select CPU_FREQ_TABLE |
1da177e4 LT |
144 | help |
145 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
146 | The governor does a periodic polling and | |
147 | changes frequency based on the CPU utilization. | |
148 | The support for this governor depends on CPU capability to | |
149 | do fast frequency switching (i.e, very low latency frequency | |
150 | transitions). | |
151 | ||
9101be53 MF |
152 | To compile this driver as a module, choose M here: the |
153 | module will be called cpufreq_ondemand. | |
154 | ||
1da177e4 LT |
155 | For details, take a look at linux/Documentation/cpu-freq. |
156 | ||
157 | If in doubt, say N. | |
158 | ||
b9170836 DJ |
159 | config CPU_FREQ_GOV_CONSERVATIVE |
160 | tristate "'conservative' cpufreq governor" | |
161 | depends on CPU_FREQ | |
162 | help | |
163 | 'conservative' - this driver is rather similar to the 'ondemand' | |
164 | governor both in its source code and its purpose, the difference is | |
165 | its optimisation for better suitability in a battery powered | |
166 | environment. The frequency is gracefully increased and decreased | |
167 | rather than jumping to 100% when speed is required. | |
168 | ||
169 | If you have a desktop machine then you should really be considering | |
170 | the 'ondemand' governor instead, however if you are using a laptop, | |
171 | PDA or even an AMD64 based computer (due to the unacceptable | |
172 | step-by-step latency issues between the minimum and maximum frequency | |
173 | transitions in the CPU) you will probably want to use this governor. | |
174 | ||
9101be53 MF |
175 | To compile this driver as a module, choose M here: the |
176 | module will be called cpufreq_conservative. | |
177 | ||
b9170836 DJ |
178 | For details, take a look at linux/Documentation/cpu-freq. |
179 | ||
180 | If in doubt, say N. | |
181 | ||
bb0a56ec DJ |
182 | menu "x86 CPU frequency scaling drivers" |
183 | depends on X86 | |
184 | source "drivers/cpufreq/Kconfig.x86" | |
185 | endmenu | |
186 | ||
187 | endif | |
188 | endmenu |