2 # x86 CPU Frequency scaling drivers
5 config X86_INTEL_PSTATE
6 bool
"Intel P state control"
9 This driver provides a P state for Intel core processors.
10 The driver implements an internal governor
and will become
11 the scaling driver
and governor for Sandy bridge processors.
13 When
this driver is enabled it will become the preferred
14 scaling driver for Sandy bridge processors.
18 config X86_PCC_CPUFREQ
19 tristate
"Processor Clocking Control interface driver"
20 depends on ACPI
&& ACPI_PROCESSOR
22 This driver adds support for the PCC interface.
24 For details
, take a look
at:
25 <file:Documentation
/cpu
-freq
/pcc
-cpufreq.txt
>.
27 To compile
this driver as a module
, choose M
here: the
28 module will be called pcc
-cpufreq.
32 config X86_ACPI_CPUFREQ
33 tristate
"ACPI Processor P-States driver"
34 depends on ACPI_PROCESSOR
36 This driver adds a CPUFreq driver which utilizes the ACPI
37 Processor Performance States.
38 This driver also supports Intel Enhanced Speedstep
and newer
41 To compile
this driver as a module
, choose M
here: the
42 module will be called acpi
-cpufreq.
44 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
48 config X86_ACPI_CPUFREQ_CPB
50 bool
"Legacy cpb sysfs knob support for AMD CPUs"
51 depends on X86_ACPI_CPUFREQ
&& CPU_SUP_AMD
53 The powernow
-k8 driver used to provide a sysfs knob called
"cpb"
54 to disable the Core Performance Boosting feature of AMD CPUs.
This
55 file has now been superseded by the more generic
"boost" entry.
57 By enabling
this option the acpi_cpufreq driver provides the old
58 entry in addition to the new boost ones
, for compatibility reasons.
60 config X86_SFI_CPUFREQ
61 tristate
"SFI Performance-States driver"
62 depends on X86_INTEL_MID
&& SFI
64 This adds a CPUFreq driver for some Silvermont based Intel Atom
65 architectures like Z34xx
and Z35xx which enumerate processor
66 performance states through SFI.
71 tristate
"AMD Elan SC400 and SC410"
74 This adds the CPUFreq driver for AMD Elan SC400
and SC410
77 You need to specify the processor maximum speed as boot
78 parameter: elanfreq
=maxspeed
(in kHz
) or as module
81 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
86 tristate
"AMD Elan SC520"
89 This adds the CPUFreq driver for AMD Elan SC520 processor.
91 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
96 config X86_POWERNOW_K6
97 tristate
"AMD Mobile K6-2/K6-3 PowerNow!"
100 This adds the CPUFreq driver for mobile AMD K6
-2+ and mobile
101 AMD K6
-3+ processors.
103 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
107 config X86_POWERNOW_K7
108 tristate
"AMD Mobile Athlon/Duron PowerNow!"
111 This adds the CPUFreq driver for mobile AMD K7 mobile processors.
113 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
117 config X86_POWERNOW_K7_ACPI
119 depends on X86_POWERNOW_K7
&& ACPI_PROCESSOR
120 depends on
!(X86_POWERNOW_K7
= y
&& ACPI_PROCESSOR
= m
)
124 config X86_POWERNOW_K8
125 tristate
"AMD Opteron/Athlon64 PowerNow!"
126 depends on ACPI
&& ACPI_PROCESSOR
&& X86_ACPI_CPUFREQ
128 This adds the CPUFreq driver for K8
/early Opteron
/Athlon64 processors.
129 Support for K10
and newer processors is now
in acpi
-cpufreq.
131 To compile
this driver as a module
, choose M
here: the
132 module will be called powernow
-k8.
134 For details
, take a look at
<file:Documentation
/cpu
-freq
/>.
136 config X86_AMD_FREQ_SENSITIVITY
137 tristate
"AMD frequency sensitivity feedback powersave bias"
138 depends on CPU_FREQ_GOV_ONDEMAND
&& X86_ACPI_CPUFREQ
&& CPU_SUP_AMD
140 This adds AMD
-specific powersave bias function to the ondemand
141 governor
, which allows it to make more power
-conscious frequency
142 change decisions based on feedback from hardware
(available on AMD
143 Family
16h and above
).
145 Hardware feedback tells software how
"sensitive" to frequency changes
146 the CPUs
' workloads are. CPU-bound workloads will be more sensitive
147 -- they will perform better as frequency increases. Memory/IO-bound
148 workloads will be less sensitive -- they will not necessarily perform
149 better as frequency increases.
153 config X86_GX_SUSPMOD
154 tristate "Cyrix MediaGX/NatSemi Geode Suspend Modulation"
155 depends on X86_32 && PCI
157 This add the CPUFreq driver for NatSemi Geode processors which
158 support suspend modulation.
160 For details, take a look at <file:Documentation/cpu-freq/>.
164 config X86_SPEEDSTEP_CENTRINO
165 tristate "Intel Enhanced SpeedStep (deprecated)"
166 select X86_SPEEDSTEP_CENTRINO_TABLE if X86_32
167 depends on X86_32 || (X86_64 && ACPI_PROCESSOR)
169 This is deprecated and this functionality is now merged into
170 acpi_cpufreq (X86_ACPI_CPUFREQ). Use that driver instead of
172 This adds the CPUFreq driver for Enhanced SpeedStep enabled
173 mobile CPUs. This means Intel Pentium M (Centrino) CPUs
174 or 64bit enabled Intel Xeons.
176 To compile this driver as a module, choose M here: the
177 module will be called speedstep-centrino.
179 For details, take a look at <file:Documentation/cpu-freq/>.
183 config X86_SPEEDSTEP_CENTRINO_TABLE
184 bool "Built-in tables for Banias CPUs"
185 depends on X86_32 && X86_SPEEDSTEP_CENTRINO
188 Use built-in tables for Banias CPUs if ACPI encoding
193 config X86_SPEEDSTEP_ICH
194 tristate "Intel Speedstep on ICH-M chipsets (ioport interface)"
197 This adds the CPUFreq driver for certain mobile Intel Pentium III
198 (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
199 mobile Intel Pentium 4 P4-M on systems which have an Intel ICH2,
200 ICH3 or ICH4 southbridge.
202 For details, take a look at <file:Documentation/cpu-freq/>.
206 config X86_SPEEDSTEP_SMI
207 tristate "Intel SpeedStep on 440BX/ZX/MX chipsets (SMI interface)"
210 This adds the CPUFreq driver for certain mobile Intel Pentium III
211 (Coppermine), all mobile Intel Pentium III-M (Tualatin)
212 on systems which have an Intel 440BX/ZX/MX southbridge.
214 For details, take a look at <file:Documentation/cpu-freq/>.
218 config X86_P4_CLOCKMOD
219 tristate "Intel Pentium 4 clock modulation"
221 This adds the CPUFreq driver for Intel Pentium 4 / XEON
222 processors. When enabled it will lower CPU temperature by skipping
225 This driver should be only used in exceptional
226 circumstances when very low power is needed because it causes severe
227 slowdowns and noticeable latencies. Normally Speedstep should be used
230 To compile this driver as a module, choose M here: the
231 module will be called p4-clockmod.
233 For details, take a look at <file:Documentation/cpu-freq/>.
235 Unless you are absolutely sure say N.
237 config X86_CPUFREQ_NFORCE2
238 tristate "nVidia nForce2 FSB changing"
241 This adds the CPUFreq driver for FSB changing on nVidia nForce2
244 For details, take a look at <file:Documentation/cpu-freq/>.
249 tristate "Transmeta LongRun"
252 This adds the CPUFreq driver for Transmeta Crusoe and Efficeon processors
253 which support LongRun.
255 For details, take a look at <file:Documentation/cpu-freq/>.
260 tristate "VIA Cyrix III Longhaul"
261 depends on X86_32 && ACPI_PROCESSOR
263 This adds the CPUFreq driver for VIA Samuel/CyrixIII,
264 VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
267 For details, take a look at <file:Documentation/cpu-freq/>.
271 config X86_E_POWERSAVER
272 tristate "VIA C7 Enhanced PowerSaver (DANGEROUS)"
273 depends on X86_32 && ACPI_PROCESSOR
275 This adds the CPUFreq driver for VIA C7 processors. However, this driver
276 does not have any safeguards to prevent operating the CPU out of spec
277 and is thus considered dangerous. Please use the regular ACPI cpufreq
278 driver, enabled by CONFIG_X86_ACPI_CPUFREQ.
282 comment "shared options"
284 config X86_SPEEDSTEP_LIB
286 default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
288 config X86_SPEEDSTEP_RELAXED_CAP_CHECK
289 bool "Relaxed speedstep capability checks"
290 depends on X86_32 && (X86_SPEEDSTEP_SMI || X86_SPEEDSTEP_ICH)
292 Don't perform all checks for a speedstep capable system which would
293 normally be done. Some ancient
or strange systems
, though speedstep
294 capable
, don
't always indicate that they are speedstep capable. This
295 option lets the probing code bypass some of those checks if the
296 parameter "relaxed_check=1" is passed to the module.