Commit | Line | Data |
---|---|---|
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 | |
19 | def_tristate m | |
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 | |
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 | config CPU_FREQ_STAT_DETAILS | |
43 | bool "CPU frequency translation statistics details" | |
44 | depends on CPU_FREQ_STAT | |
45 | help | |
46 | This will show detail CPU frequency translation table in sysfs file | |
47 | system | |
48 | ||
33100108 DJ |
49 | # Note that it is not currently possible to set the other governors (such as ondemand) |
50 | # as the default, since if they fail to initialise, cpufreq will be | |
51 | # left in an undefined state. | |
52 | ||
1da177e4 LT |
53 | choice |
54 | prompt "Default CPUFreq governor" | |
55 | default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110 | |
56 | default CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
57 | help | |
58 | This option sets which CPUFreq governor shall be loaded at | |
59 | startup. If in doubt, select 'performance'. | |
60 | ||
61 | config CPU_FREQ_DEFAULT_GOV_PERFORMANCE | |
62 | bool "performance" | |
63 | select CPU_FREQ_GOV_PERFORMANCE | |
64 | help | |
65 | Use the CPUFreq governor 'performance' as default. This sets | |
66 | the frequency statically to the highest frequency supported by | |
67 | the CPU. | |
68 | ||
69 | config CPU_FREQ_DEFAULT_GOV_USERSPACE | |
70 | bool "userspace" | |
71 | select CPU_FREQ_GOV_USERSPACE | |
72 | help | |
73 | Use the CPUFreq governor 'userspace' as default. This allows | |
74 | you to set the CPU frequency manually or when an userspace | |
75 | program shall be able to set the CPU dynamically without having | |
76 | to enable the userspace governor manually. | |
77 | ||
78 | endchoice | |
79 | ||
80 | config CPU_FREQ_GOV_PERFORMANCE | |
81 | tristate "'performance' governor" | |
82 | help | |
83 | This cpufreq governor sets the frequency statically to the | |
84 | highest available CPU frequency. | |
85 | ||
86 | If in doubt, say Y. | |
87 | ||
88 | config CPU_FREQ_GOV_POWERSAVE | |
89 | tristate "'powersave' governor" | |
90 | help | |
91 | This cpufreq governor sets the frequency statically to the | |
92 | lowest available CPU frequency. | |
93 | ||
94 | If in doubt, say Y. | |
95 | ||
96 | config CPU_FREQ_GOV_USERSPACE | |
97 | tristate "'userspace' governor for userspace frequency scaling" | |
98 | help | |
99 | Enable this cpufreq governor when you either want to set the | |
100 | CPU frequency manually or when an userspace program shall | |
101 | be able to set the CPU dynamically, like on LART | |
102 | <http://www.lart.tudelft.nl/> | |
103 | ||
104 | For details, take a look at <file:Documentation/cpu-freq/>. | |
105 | ||
106 | If in doubt, say Y. | |
107 | ||
108 | config CPU_FREQ_GOV_ONDEMAND | |
109 | tristate "'ondemand' cpufreq policy governor" | |
110 | help | |
111 | 'ondemand' - This driver adds a dynamic cpufreq policy governor. | |
112 | The governor does a periodic polling and | |
113 | changes frequency based on the CPU utilization. | |
114 | The support for this governor depends on CPU capability to | |
115 | do fast frequency switching (i.e, very low latency frequency | |
116 | transitions). | |
117 | ||
118 | For details, take a look at linux/Documentation/cpu-freq. | |
119 | ||
120 | If in doubt, say N. | |
121 | ||
b9170836 DJ |
122 | config CPU_FREQ_GOV_CONSERVATIVE |
123 | tristate "'conservative' cpufreq governor" | |
124 | depends on CPU_FREQ | |
125 | help | |
126 | 'conservative' - this driver is rather similar to the 'ondemand' | |
127 | governor both in its source code and its purpose, the difference is | |
128 | its optimisation for better suitability in a battery powered | |
129 | environment. The frequency is gracefully increased and decreased | |
130 | rather than jumping to 100% when speed is required. | |
131 | ||
132 | If you have a desktop machine then you should really be considering | |
133 | the 'ondemand' governor instead, however if you are using a laptop, | |
134 | PDA or even an AMD64 based computer (due to the unacceptable | |
135 | step-by-step latency issues between the minimum and maximum frequency | |
136 | transitions in the CPU) you will probably want to use this governor. | |
137 | ||
138 | For details, take a look at linux/Documentation/cpu-freq. | |
139 | ||
140 | If in doubt, say N. | |
141 | ||
1da177e4 | 142 | endif # CPU_FREQ |