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_K8
92 tristate "AMD Opteron/Athlon64 PowerNow!"
93 depends on CPU_FREQ && EXPERIMENTAL
95 This adds the CPUFreq driver for mobile AMD Opteron/Athlon64 processors.
97 For details, take a look at <file:Documentation/cpu-freq/>.
101 config X86_GX_SUSPMOD
102 tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
105 This add the CPUFreq driver for NatSemi Geode processors which
106 support suspend modulation.
108 For details, take a look at <file:Documentation/cpu-freq/>.
112 config X86_SPEEDSTEP_CENTRINO
113 tristate "Intel Enhanced SpeedStep"
114 depends on CPU_FREQ_TABLE
116 This adds the CPUFreq driver for Enhanced SpeedStep enabled
117 mobile CPUs. This means Intel Pentium M (Centrino) CPUs.
119 For details, take a look at <file:Documentation/cpu-freq/>.
123 config X86_SPEEDSTEP_CENTRINO_TABLE
125 depends on X86_SPEEDSTEP_CENTRINO
128 config X86_SPEEDSTEP_CENTRINO_ACPI
129 bool "Use ACPI tables to decode valid frequency/voltage pairs (EXPERIMENTAL)"
130 depends on EXPERIMENTAL
131 depends on ((X86_SPEEDSTEP_CENTRINO = "m" && ACPI_PROCESSOR) || (X86_SPEEDSTEP_CENTRINO = "y" && ACPI_PROCESSOR = "y"))
133 Use primarily the information provided in the BIOS ACPI tables
134 to determine valid CPU frequency and voltage pairings.
138 config X86_SPEEDSTEP_ICH
139 tristate "Intel Speedstep on ICH-M chipsets (ioport interface)"
140 depends on CPU_FREQ_TABLE
142 This adds the CPUFreq driver for certain mobile Intel Pentium III
143 (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
144 mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
145 ICH3 or ICH4 southbridge.
147 For details, take a look at <file:Documentation/cpu-freq/>.
151 config X86_SPEEDSTEP_SMI
152 tristate "Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)"
153 depends on CPU_FREQ_TABLE && EXPERIMENTAL
155 This adds the CPUFreq driver for certain mobile Intel Pentium III
156 (Coppermine), all mobile Intel Pentium III-M (Tualatin)
157 on systems which have an Intel 440BX/ZX/MX southbridge.
159 For details, take a look at <file:Documentation/cpu-freq/>.
163 config X86_P4_CLOCKMOD
164 tristate "Intel Pentium 4 clock modulation"
165 depends on CPU_FREQ_TABLE
167 This adds the CPUFreq driver for Intel Pentium 4 / XEON
170 For details, take a look at <file:Documentation/cpu-freq/>.
174 config X86_SPEEDSTEP_LIB
176 depends on (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
177 default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
179 config X86_SPEEDSTEP_RELAXED_CAP_CHECK
180 bool "Relaxed speedstep capability checks"
181 depends on (X86_SPEEDSTEP_SMI || X86_SPEEDSTEP_ICH)
183 Don't perform all checks for a speedstep capable system which would
184 normally be done. Some ancient or strange systems, though speedstep
185 capable, don't always indicate that they are speedstep capable. This
186 option let's the probing code bypass some of those checks if the
187 parameter "relaxed_check=1" is passed to the module.
190 tristate "Transmeta LongRun"
193 This adds the CPUFreq driver for Transmeta Crusoe processors which
196 For details, take a look at <file:Documentation/cpu-freq/>.
201 tristate "VIA Cyrix III Longhaul"
202 depends on CPU_FREQ_TABLE
204 This adds the CPUFreq driver for VIA Samuel/CyrixIII,
205 VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
208 For details, take a look at <file:Documentation/cpu-freq/>.