2 # CPU Frequency scaling
5 menu "CPU Frequency scaling"
7 source "drivers/cpufreq/Kconfig"
11 comment "CPUFreq processor drivers"
13 config X86_ACPI_CPUFREQ
14 tristate "ACPI Processor P-States driver"
16 depends on ACPI_PROCESSOR
18 This driver adds a CPUFreq driver which utilizes the ACPI
19 Processor Performance States.
20 This driver also supports Intel Enhanced Speedstep.
22 To compile this driver as a module, choose M here: the
23 module will be called acpi-cpufreq.
25 For details, take a look at <file:Documentation/cpu-freq/>.
30 tristate "AMD Elan SC400 and SC410"
34 This adds the CPUFreq driver for AMD Elan SC400 and SC410
37 You need to specify the processor maximum speed as boot
38 parameter: elanfreq=maxspeed (in kHz) or as module
41 For details, take a look at <file:Documentation/cpu-freq/>.
46 tristate "AMD Elan SC520"
50 This adds the CPUFreq driver for AMD Elan SC520 processor.
52 For details, take a look at <file:Documentation/cpu-freq/>.
57 config X86_POWERNOW_K6
58 tristate "AMD Mobile K6-2/K6-3 PowerNow!"
62 This adds the CPUFreq driver for mobile AMD K6-2+ and mobile
65 For details, take a look at <file:Documentation/cpu-freq/>.
69 config X86_POWERNOW_K7
70 tristate "AMD Mobile Athlon/Duron PowerNow!"
74 This adds the CPUFreq driver for mobile AMD K7 mobile processors.
76 For details, take a look at <file:Documentation/cpu-freq/>.
80 config X86_POWERNOW_K7_ACPI
82 depends on X86_POWERNOW_K7 && ACPI_PROCESSOR
83 depends on !(X86_POWERNOW_K7 = y && ACPI_PROCESSOR = m)
87 config X86_POWERNOW_K8
88 tristate "AMD Opteron/Athlon64 PowerNow!"
90 depends on ACPI && ACPI_PROCESSOR
92 This adds the CPUFreq driver for K8/K10 Opteron/Athlon64 processors.
94 To compile this driver as a module, choose M here: the
95 module will be called powernow-k8.
97 For details, take a look at <file:Documentation/cpu-freq/>.
100 tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
101 depends on X86_32 && PCI
103 This add the CPUFreq driver for NatSemi Geode processors which
104 support suspend modulation.
106 For details, take a look at <file:Documentation/cpu-freq/>.
110 config X86_SPEEDSTEP_CENTRINO
111 tristate "Intel Enhanced SpeedStep (deprecated)"
112 select CPU_FREQ_TABLE
113 select X86_SPEEDSTEP_CENTRINO_TABLE if X86_32
114 depends on X86_32 || (X86_64 && ACPI_PROCESSOR)
116 This is deprecated and this functionality is now merged into
117 acpi_cpufreq (X86_ACPI_CPUFREQ). Use that driver instead of
119 This adds the CPUFreq driver for Enhanced SpeedStep enabled
120 mobile CPUs. This means Intel Pentium M (Centrino) CPUs
121 or 64bit enabled Intel Xeons.
123 To compile this driver as a module, choose M here: the
124 module will be called speedstep-centrino.
126 For details, take a look at <file:Documentation/cpu-freq/>.
130 config X86_SPEEDSTEP_CENTRINO_TABLE
131 bool "Built-in tables for Banias CPUs"
132 depends on X86_32 && X86_SPEEDSTEP_CENTRINO
135 Use built-in tables for Banias CPUs if ACPI encoding
140 config X86_SPEEDSTEP_ICH
141 tristate "Intel Speedstep on ICH-M chipsets (ioport interface)"
142 select CPU_FREQ_TABLE
145 This adds the CPUFreq driver for certain mobile Intel Pentium III
146 (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
147 mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
148 ICH3 or ICH4 southbridge.
150 For details, take a look at <file:Documentation/cpu-freq/>.
154 config X86_SPEEDSTEP_SMI
155 tristate "Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)"
156 select CPU_FREQ_TABLE
157 depends on X86_32 && EXPERIMENTAL
159 This adds the CPUFreq driver for certain mobile Intel Pentium III
160 (Coppermine), all mobile Intel Pentium III-M (Tualatin)
161 on systems which have an Intel 440BX/ZX/MX southbridge.
163 For details, take a look at <file:Documentation/cpu-freq/>.
167 config X86_P4_CLOCKMOD
168 tristate "Intel Pentium 4 clock modulation"
169 select CPU_FREQ_TABLE
171 This adds the CPUFreq driver for Intel Pentium 4 / XEON
172 processors. When enabled it will lower CPU temperature by skipping
175 This driver should be only used in exceptional
176 circumstances when very low power is needed because it causes severe
177 slowdowns and noticeable latencies. Normally Speedstep should be used
180 To compile this driver as a module, choose M here: the
181 module will be called p4-clockmod.
183 For details, take a look at <file:Documentation/cpu-freq/>.
185 Unless you are absolutely sure say N.
187 config X86_CPUFREQ_NFORCE2
188 tristate "nVidia nForce2 FSB changing"
189 depends on X86_32 && EXPERIMENTAL
191 This adds the CPUFreq driver for FSB changing on nVidia nForce2
194 For details, take a look at <file:Documentation/cpu-freq/>.
199 tristate "Transmeta LongRun"
202 This adds the CPUFreq driver for Transmeta Crusoe and Efficeon processors
203 which support LongRun.
205 For details, take a look at <file:Documentation/cpu-freq/>.
210 tristate "VIA Cyrix III Longhaul"
211 select CPU_FREQ_TABLE
212 depends on X86_32 && ACPI_PROCESSOR
214 This adds the CPUFreq driver for VIA Samuel/CyrixIII,
215 VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
218 For details, take a look at <file:Documentation/cpu-freq/>.
222 config X86_E_POWERSAVER
223 tristate "VIA C7 Enhanced PowerSaver (DANGEROUS)"
224 select CPU_FREQ_TABLE
225 depends on X86_32 && EXPERIMENTAL
227 This adds the CPUFreq driver for VIA C7 processors. However, this driver
228 does not have any safeguards to prevent operating the CPU out of spec
229 and is thus considered dangerous. Please use the regular ACPI cpufreq
230 driver, enabled by CONFIG_X86_ACPI_CPUFREQ.
234 comment "shared options"
236 config X86_SPEEDSTEP_LIB
238 default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
240 config X86_SPEEDSTEP_RELAXED_CAP_CHECK
241 bool "Relaxed speedstep capability checks"
242 depends on X86_32 && (X86_SPEEDSTEP_SMI || X86_SPEEDSTEP_ICH)
244 Don't perform all checks for a speedstep capable system which would
245 normally be done. Some ancient or strange systems, though speedstep
246 capable, don't always indicate that they are speedstep capable. This
247 option lets the probing code bypass some of those checks if the
248 parameter "relaxed_check=1" is passed to the module.