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1menu "CPU Frequency scaling"
2
3config 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
18if CPU_FREQ
19
20config CPU_FREQ_GOV_COMMON
21 bool
22
23config CPU_FREQ_STAT
24 tristate "CPU frequency translation statistics"
25 default y
26 help
27 This driver exports CPU frequency statistics information through sysfs
28 file system.
29
30 To compile this driver as a module, choose M here: the
31 module will be called cpufreq_stats.
32
33 If in doubt, say N.
34
35config CPU_FREQ_STAT_DETAILS
36 bool "CPU frequency translation statistics details"
37 depends on CPU_FREQ_STAT
38 help
39 This will show detail CPU frequency translation table in sysfs file
40 system.
41
42 If in doubt, say N.
43
44choice
45 prompt "Default CPUFreq governor"
46 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
47 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
48 help
49 This option sets which CPUFreq governor shall be loaded at
50 startup. If in doubt, select 'performance'.
51
52config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
53 bool "performance"
54 select CPU_FREQ_GOV_PERFORMANCE
55 help
56 Use the CPUFreq governor 'performance' as default. This sets
57 the frequency statically to the highest frequency supported by
58 the CPU.
59
60config CPU_FREQ_DEFAULT_GOV_POWERSAVE
61 bool "powersave"
62 depends on EXPERT
63 select CPU_FREQ_GOV_POWERSAVE
64 help
65 Use the CPUFreq governor 'powersave' as default. This sets
66 the frequency statically to the lowest frequency supported by
67 the CPU.
68
69config 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 a userspace
75 program shall be able to set the CPU dynamically without having
76 to enable the userspace governor manually.
77
78config CPU_FREQ_DEFAULT_GOV_ONDEMAND
79 bool "ondemand"
80 select CPU_FREQ_GOV_ONDEMAND
81 select CPU_FREQ_GOV_PERFORMANCE
82 help
83 Use the CPUFreq governor 'ondemand' as default. This allows
84 you to get a full dynamic frequency capable system by simply
85 loading your cpufreq low-level hardware driver.
86 Be aware that not all cpufreq drivers support the ondemand
87 governor. If unsure have a look at the help section of the
88 driver. Fallback governor will be the performance governor.
89
90config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
91 bool "conservative"
92 select CPU_FREQ_GOV_CONSERVATIVE
93 select CPU_FREQ_GOV_PERFORMANCE
94 help
95 Use the CPUFreq governor 'conservative' as default. This allows
96 you to get a full dynamic frequency capable system by simply
97 loading your cpufreq low-level hardware driver.
98 Be aware that not all cpufreq drivers support the conservative
99 governor. If unsure have a look at the help section of the
100 driver. Fallback governor will be the performance governor.
101endchoice
102
103config CPU_FREQ_GOV_PERFORMANCE
104 tristate "'performance' governor"
105 help
106 This cpufreq governor sets the frequency statically to the
107 highest available CPU frequency.
108
109 To compile this driver as a module, choose M here: the
110 module will be called cpufreq_performance.
111
112 If in doubt, say Y.
113
114config CPU_FREQ_GOV_POWERSAVE
115 tristate "'powersave' governor"
116 help
117 This cpufreq governor sets the frequency statically to the
118 lowest available CPU frequency.
119
120 To compile this driver as a module, choose M here: the
121 module will be called cpufreq_powersave.
122
123 If in doubt, say Y.
124
125config CPU_FREQ_GOV_USERSPACE
126 tristate "'userspace' governor for userspace frequency scaling"
127 help
128 Enable this cpufreq governor when you either want to set the
129 CPU frequency manually or when a userspace program shall
130 be able to set the CPU dynamically, like on LART
131 <http://www.lartmaker.nl/>.
132
133 To compile this driver as a module, choose M here: the
134 module will be called cpufreq_userspace.
135
136 For details, take a look at <file:Documentation/cpu-freq/>.
137
138 If in doubt, say Y.
139
140config CPU_FREQ_GOV_ONDEMAND
141 tristate "'ondemand' cpufreq policy governor"
142 select CPU_FREQ_GOV_COMMON
143 help
144 'ondemand' - This driver adds a dynamic cpufreq policy governor.
145 The governor does a periodic polling and
146 changes frequency based on the CPU utilization.
147 The support for this governor depends on CPU capability to
148 do fast frequency switching (i.e, very low latency frequency
149 transitions).
150
151 To compile this driver as a module, choose M here: the
152 module will be called cpufreq_ondemand.
153
154 For details, take a look at linux/Documentation/cpu-freq.
155
156 If in doubt, say N.
157
158config CPU_FREQ_GOV_CONSERVATIVE
159 tristate "'conservative' cpufreq governor"
160 depends on CPU_FREQ
161 select CPU_FREQ_GOV_COMMON
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
175 To compile this driver as a module, choose M here: the
176 module will be called cpufreq_conservative.
177
178 For details, take a look at linux/Documentation/cpu-freq.
179
180 If in doubt, say N.
181
182config GENERIC_CPUFREQ_CPU0
183 tristate "Generic CPU0 cpufreq driver"
184 depends on HAVE_CLK && REGULATOR && PM_OPP && OF
185 help
186 This adds a generic cpufreq driver for CPU0 frequency management.
187 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
188 systems which share clock and voltage across all CPUs.
189
190 If in doubt, say N.
191
192menu "x86 CPU frequency scaling drivers"
193depends on X86
194source "drivers/cpufreq/Kconfig.x86"
195endmenu
196
197menu "ARM CPU frequency scaling drivers"
198depends on ARM
199source "drivers/cpufreq/Kconfig.arm"
200endmenu
201
202menu "AVR32 CPU frequency scaling drivers"
203depends on AVR32
204
205config AVR32_AT32AP_CPUFREQ
206 bool "CPU frequency driver for AT32AP"
207 depends on PLATFORM_AT32AP
208 default n
209 help
210 This enables the CPU frequency driver for AT32AP processors.
211 If in doubt, say N.
212
213endmenu
214
215menu "CPUFreq processor drivers"
216depends on IA64
217
218config IA64_ACPI_CPUFREQ
219 tristate "ACPI Processor P-States driver"
220 depends on ACPI_PROCESSOR
221 help
222 This driver adds a CPUFreq driver which utilizes the ACPI
223 Processor Performance States.
224
225 For details, take a look at <file:Documentation/cpu-freq/>.
226
227 If in doubt, say N.
228
229endmenu
230
231menu "MIPS CPUFreq processor drivers"
232depends on MIPS
233
234config LOONGSON2_CPUFREQ
235 tristate "Loongson2 CPUFreq Driver"
236 help
237 This option adds a CPUFreq driver for loongson processors which
238 support software configurable cpu frequency.
239
240 Loongson2F and it's successors support this feature.
241
242 For details, take a look at <file:Documentation/cpu-freq/>.
243
244 If in doubt, say N.
245
246endmenu
247
248menu "PowerPC CPU frequency scaling drivers"
249depends on PPC32 || PPC64
250source "drivers/cpufreq/Kconfig.powerpc"
251endmenu
252
253menu "SPARC CPU frequency scaling drivers"
254depends on SPARC64
255config SPARC_US3_CPUFREQ
256 tristate "UltraSPARC-III CPU Frequency driver"
257 help
258 This adds the CPUFreq driver for UltraSPARC-III processors.
259
260 For details, take a look at <file:Documentation/cpu-freq>.
261
262 If in doubt, say N.
263
264config SPARC_US2E_CPUFREQ
265 tristate "UltraSPARC-IIe CPU Frequency driver"
266 help
267 This adds the CPUFreq driver for UltraSPARC-IIe processors.
268
269 For details, take a look at <file:Documentation/cpu-freq>.
270
271 If in doubt, say N.
272endmenu
273
274menu "SH CPU Frequency scaling"
275depends on SUPERH
276config SH_CPU_FREQ
277 tristate "SuperH CPU Frequency driver"
278 help
279 This adds the cpufreq driver for SuperH. Any CPU that supports
280 clock rate rounding through the clock framework can use this
281 driver. While it will make the kernel slightly larger, this is
282 harmless for CPUs that don't support rate rounding. The driver
283 will also generate a notice in the boot log before disabling
284 itself if the CPU in question is not capable of rate rounding.
285
286 For details, take a look at <file:Documentation/cpu-freq>.
287
288 If unsure, say N.
289endmenu
290
291endif
292endmenu