2 # CPU Frequency scaling
5 menu "CPU Frequency scaling"
8 bool "CPU Frequency scaling"
10 Clock scaling allows you to change the clock speed of CPUs on the
11 fly. This is a nice method to save battery power on notebooks,
12 because the lower the clock speed, the less power the CPU consumes.
14 For more information, take a look at <file:Documentation/cpu-freq/>
15 or at <http://www.codemonkey.org.uk/projects/cpufreq/>
19 source "drivers/cpufreq/Kconfig"
22 tristate "CPU frequency table helpers"
26 Many CPUFreq drivers use these helpers, so only say N here if
27 the CPUFreq driver of your choice doesn't need these helpers.
31 comment "CPUFreq processor drivers"
34 config X86_ACPI_CPUFREQ
35 tristate "ACPI Processor P-States driver"
36 depends on CPU_FREQ_TABLE && ACPI_PROCESSOR
38 This driver adds a CPUFreq driver which utilizes the ACPI
39 Processor Performance States.
41 For details, take a look at <file:Documentation/cpu-freq/>.
45 config X86_ACPI_CPUFREQ_PROC_INTF
46 bool "/proc/acpi/processor/../performance interface (deprecated)"
47 depends on X86_ACPI_CPUFREQ && PROC_FS
49 This enables the deprecated /proc/acpi/processor/../performance
50 interface. While it is helpful for debugging, the generic,
51 cross-architecture cpufreq interfaces should be used.
57 depends on CPU_FREQ_TABLE && X86_ELAN
59 This adds the CPUFreq driver for AMD Elan SC400 and SC410
62 You need to specify the processor maximum speed as boot
63 parameter: elanfreq=maxspeed (in kHz) or as module
66 For details, take a look at <file:Documentation/cpu-freq/>.
70 config X86_POWERNOW_K6
71 tristate "AMD Mobile K6-2/K6-3 PowerNow!"
72 depends on CPU_FREQ_TABLE
74 This adds the CPUFreq driver for mobile AMD K6-2+ and mobile
77 For details, take a look at <file:Documentation/cpu-freq/>.
81 config X86_POWERNOW_K7
82 tristate "AMD Mobile Athlon/Duron PowerNow!"
83 depends on CPU_FREQ_TABLE
85 This adds the CPUFreq driver for mobile AMD K7 mobile processors.
87 For details, take a look at <file:Documentation/cpu-freq/>.
91 config X86_POWERNOW_K7_ACPI
93 depends on ((X86_POWERNOW_K7 = "m" && ACPI_PROCESSOR) || (X86_POWERNOW_K7 = "y" && ACPI_PROCESSOR = "y"))
96 config X86_POWERNOW_K8
97 tristate "AMD Opteron/Athlon64 PowerNow!"
98 depends on CPU_FREQ && EXPERIMENTAL
100 This adds the CPUFreq driver for mobile AMD Opteron/Athlon64 processors.
102 For details, take a look at <file:Documentation/cpu-freq/>.
106 config X86_POWERNOW_K8_ACPI
108 depends on ((X86_POWERNOW_K8 = "m" && ACPI_PROCESSOR) || (X86_POWERNOW_K8 = "y" && ACPI_PROCESSOR = "y"))
111 config X86_GX_SUSPMOD
112 tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
115 This add the CPUFreq driver for NatSemi Geode processors which
116 support suspend modulation.
118 For details, take a look at <file:Documentation/cpu-freq/>.
122 config X86_SPEEDSTEP_CENTRINO
123 tristate "Intel Enhanced SpeedStep"
124 depends on CPU_FREQ_TABLE
126 This adds the CPUFreq driver for Enhanced SpeedStep enabled
127 mobile CPUs. This means Intel Pentium M (Centrino) CPUs.
129 For details, take a look at <file:Documentation/cpu-freq/>.
133 config X86_SPEEDSTEP_CENTRINO_TABLE
135 depends on X86_SPEEDSTEP_CENTRINO
138 config X86_SPEEDSTEP_CENTRINO_ACPI
139 bool "Use ACPI tables to decode valid frequency/voltage pairs (EXPERIMENTAL)"
140 depends on EXPERIMENTAL
141 depends on ((X86_SPEEDSTEP_CENTRINO = "m" && ACPI_PROCESSOR) || (X86_SPEEDSTEP_CENTRINO = "y" && ACPI_PROCESSOR = "y"))
143 Use primarily the information provided in the BIOS ACPI tables
144 to determine valid CPU frequency and voltage pairings.
148 config X86_SPEEDSTEP_ICH
149 tristate "Intel Speedstep on ICH-M chipsets (ioport interface)"
150 depends on CPU_FREQ_TABLE
152 This adds the CPUFreq driver for certain mobile Intel Pentium III
153 (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
154 mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
155 ICH3 or ICH4 southbridge.
157 For details, take a look at <file:Documentation/cpu-freq/>.
161 config X86_SPEEDSTEP_SMI
162 tristate "Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)"
163 depends on CPU_FREQ_TABLE && EXPERIMENTAL
165 This adds the CPUFreq driver for certain mobile Intel Pentium III
166 (Coppermine), all mobile Intel Pentium III-M (Tualatin)
167 on systems which have an Intel 440BX/ZX/MX southbridge.
169 For details, take a look at <file:Documentation/cpu-freq/>.
173 config X86_P4_CLOCKMOD
174 tristate "Intel Pentium 4 clock modulation"
175 depends on CPU_FREQ_TABLE
177 This adds the CPUFreq driver for Intel Pentium 4 / XEON
180 For details, take a look at <file:Documentation/cpu-freq/>.
184 config X86_SPEEDSTEP_LIB
186 depends on (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
187 default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
189 config X86_SPEEDSTEP_RELAXED_CAP_CHECK
190 bool "Relaxed speedstep capability checks"
191 depends on (X86_SPEEDSTEP_SMI || X86_SPEEDSTEP_ICH)
193 Don't perform all checks for a speedstep capable system which would
194 normally be done. Some ancient or strange systems, though speedstep
195 capable, don't always indicate that they are speedstep capable. This
196 option let's the probing code bypass some of those checks if the
197 parameter "relaxed_check=1" is passed to the module.
200 tristate "Transmeta LongRun"
203 This adds the CPUFreq driver for Transmeta Crusoe processors which
206 For details, take a look at <file:Documentation/cpu-freq/>.
211 tristate "VIA Cyrix III Longhaul"
212 depends on CPU_FREQ_TABLE
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/>.