[deliverable/linux.git] / drivers / cpufreq / Kconfig

config CPU_FREQ
	bool "CPU Frequency scaling"
	help
	  CPU Frequency scaling allows you to change the clock speed of 
	  CPUs on the fly. This is a nice method to save power, because 
	  the lower the CPU clock speed, the less power the CPU consumes.

	  Note that this driver doesn't automatically change the CPU
	  clock speed, you need to either enable a dynamic cpufreq governor
	  (see below) after boot, or use a userspace tool.

	  For details, take a look at <file:Documentation/cpu-freq>.

	  If in doubt, say N.

if CPU_FREQ

config CPU_FREQ_TABLE
       def_tristate m

config CPU_FREQ_DEBUG
	bool "Enable CPUfreq debugging"
	help
	  Say Y here to enable CPUfreq subsystem (including drivers)
	  debugging. You will need to activate it via the kernel
	  command line by passing
	     cpufreq.debug=<value>

	  To get <value>, add 
	       1 to activate CPUfreq core debugging,
	       2 to activate CPUfreq drivers debugging, and
	       4 to activate CPUfreq governor debugging

config CPU_FREQ_STAT
       tristate "CPU frequency translation statistics"
       select CPU_FREQ_TABLE
       default y
       help
         This driver exports CPU frequency statistics information through sysfs
         file system

config CPU_FREQ_STAT_DETAILS
       bool "CPU frequency translation statistics details"
       depends on CPU_FREQ_STAT
       help
         This will show detail CPU frequency translation table in sysfs file
         system

# Note that it is not currently possible to set the other governors (such as ondemand)
# as the default, since if they fail to initialise, cpufreq will be
# left in an undefined state.

choice
	prompt "Default CPUFreq governor"
	default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 || CPU_FREQ_SA1110
	default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
	help
	  This option sets which CPUFreq governor shall be loaded at
	  startup. If in doubt, select 'performance'.

config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
	bool "performance"
	select CPU_FREQ_GOV_PERFORMANCE
	help
	  Use the CPUFreq governor 'performance' as default. This sets
	  the frequency statically to the highest frequency supported by
	  the CPU.

config CPU_FREQ_DEFAULT_GOV_USERSPACE
	bool "userspace"
	select CPU_FREQ_GOV_USERSPACE
	help
	  Use the CPUFreq governor 'userspace' as default. This allows
	  you to set the CPU frequency manually or when an userspace 
	  program shall be able to set the CPU dynamically without having
	  to enable the userspace governor manually.

endchoice

config CPU_FREQ_GOV_PERFORMANCE
       tristate "'performance' governor"
       help
	  This cpufreq governor sets the frequency statically to the
	  highest available CPU frequency.

	  If in doubt, say Y.

config CPU_FREQ_GOV_POWERSAVE
       tristate "'powersave' governor"
       help
	  This cpufreq governor sets the frequency statically to the
	  lowest available CPU frequency.

	  If in doubt, say Y.

config CPU_FREQ_GOV_USERSPACE
       tristate "'userspace' governor for userspace frequency scaling"
       help
	  Enable this cpufreq governor when you either want to set the
	  CPU frequency manually or when an userspace program shall
	  be able to set the CPU dynamically, like on LART 
	  <http://www.lart.tudelft.nl/>

	  For details, take a look at <file:Documentation/cpu-freq/>.

	  If in doubt, say Y.

config CPU_FREQ_GOV_ONDEMAND
	tristate "'ondemand' cpufreq policy governor"
	help
	  'ondemand' - This driver adds a dynamic cpufreq policy governor.
	  The governor does a periodic polling and 
	  changes frequency based on the CPU utilization.
	  The support for this governor depends on CPU capability to
	  do fast frequency switching (i.e, very low latency frequency
	  transitions). 

	  For details, take a look at linux/Documentation/cpu-freq.

	  If in doubt, say N.

config CPU_FREQ_GOV_CONSERVATIVE
	tristate "'conservative' cpufreq governor"
	depends on CPU_FREQ
	help
	  'conservative' - this driver is rather similar to the 'ondemand'
	  governor both in its source code and its purpose, the difference is
	  its optimisation for better suitability in a battery powered
	  environment.  The frequency is gracefully increased and decreased
	  rather than jumping to 100% when speed is required.

	  If you have a desktop machine then you should really be considering
	  the 'ondemand' governor instead, however if you are using a laptop,
	  PDA or even an AMD64 based computer (due to the unacceptable
	  step-by-step latency issues between the minimum and maximum frequency
	  transitions in the CPU) you will probably want to use this governor.

	  For details, take a look at linux/Documentation/cpu-freq.

	  If in doubt, say N.

endif	# CPU_FREQ
Commit	Line	Data
1da177e4 LT	1	config CPU_FREQ
	2	bool "CPU Frequency scaling"
	3	help
	4	CPU Frequency scaling allows you to change the clock speed of
	5	CPUs on the fly. This is a nice method to save power, because
	6	the lower the CPU clock speed, the less power the CPU consumes.
	7
	8	Note that this driver doesn't automatically change the CPU
	9	clock speed, you need to either enable a dynamic cpufreq governor
	10	(see below) after boot, or use a userspace tool.
	11
	12	For details, take a look at <file:Documentation/cpu-freq>.
	13
	14	If in doubt, say N.
	15
	16	if CPU_FREQ
	17
	18	config CPU_FREQ_TABLE
	19	def_tristate m
	20
	21	config CPU_FREQ_DEBUG
	22	bool "Enable CPUfreq debugging"
	23	help
	24	Say Y here to enable CPUfreq subsystem (including drivers)
	25	debugging. You will need to activate it via the kernel
	26	command line by passing
	27	cpufreq.debug=<value>
	28
	29	To get <value>, add
	30	1 to activate CPUfreq core debugging,
	31	2 to activate CPUfreq drivers debugging, and
	32	4 to activate CPUfreq governor debugging
	33
	34	config CPU_FREQ_STAT
	35	tristate "CPU frequency translation statistics"
	36	select CPU_FREQ_TABLE
	37	default y
	38	help
	39	This driver exports CPU frequency statistics information through sysfs
	40	file system
	41
	42	config CPU_FREQ_STAT_DETAILS
	43	bool "CPU frequency translation statistics details"
	44	depends on CPU_FREQ_STAT
	45	help
	46	This will show detail CPU frequency translation table in sysfs file
	47	system
	48
33100108 DJ	49	# Note that it is not currently possible to set the other governors (such as ondemand)
	50	# as the default, since if they fail to initialise, cpufreq will be
	51	# left in an undefined state.
	52
1da177e4 LT	53	choice
	54	prompt "Default CPUFreq governor"
	55	default CPU_FREQ_DEFAULT_GOV_USERSPACE if CPU_FREQ_SA1100 \|\| CPU_FREQ_SA1110
	56	default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
	57	help
	58	This option sets which CPUFreq governor shall be loaded at
	59	startup. If in doubt, select 'performance'.
	60
	61	config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
	62	bool "performance"
	63	select CPU_FREQ_GOV_PERFORMANCE
	64	help
	65	Use the CPUFreq governor 'performance' as default. This sets
	66	the frequency statically to the highest frequency supported by
	67	the CPU.
	68
	69	config 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 an userspace
	75	program shall be able to set the CPU dynamically without having
	76	to enable the userspace governor manually.
	77
	78	endchoice
	79
	80	config CPU_FREQ_GOV_PERFORMANCE
	81	tristate "'performance' governor"
	82	help
	83	This cpufreq governor sets the frequency statically to the
	84	highest available CPU frequency.
	85
	86	If in doubt, say Y.
	87
	88	config CPU_FREQ_GOV_POWERSAVE
	89	tristate "'powersave' governor"
	90	help
	91	This cpufreq governor sets the frequency statically to the
	92	lowest available CPU frequency.
	93
	94	If in doubt, say Y.
	95
	96	config CPU_FREQ_GOV_USERSPACE
	97	tristate "'userspace' governor for userspace frequency scaling"
	98	help
	99	Enable this cpufreq governor when you either want to set the
	100	CPU frequency manually or when an userspace program shall
	101	be able to set the CPU dynamically, like on LART
	102	<http://www.lart.tudelft.nl/>
	103
	104	For details, take a look at <file:Documentation/cpu-freq/>.
	105
	106	If in doubt, say Y.
	107
	108	config CPU_FREQ_GOV_ONDEMAND
	109	tristate "'ondemand' cpufreq policy governor"
	110	help
	111	'ondemand' - This driver adds a dynamic cpufreq policy governor.
	112	The governor does a periodic polling and
	113	changes frequency based on the CPU utilization.
	114	The support for this governor depends on CPU capability to
	115	do fast frequency switching (i.e, very low latency frequency
	116	transitions).
117
118	For details, take a look at linux/Documentation/cpu-freq.
119
120	If in doubt, say N.
121
b9170836 DJ	122	config CPU_FREQ_GOV_CONSERVATIVE
	123	tristate "'conservative' cpufreq governor"
	124	depends on CPU_FREQ
	125	help
	126	'conservative' - this driver is rather similar to the 'ondemand'
	127	governor both in its source code and its purpose, the difference is
	128	its optimisation for better suitability in a battery powered
	129	environment. The frequency is gracefully increased and decreased
	130	rather than jumping to 100% when speed is required.
	131
	132	If you have a desktop machine then you should really be considering
	133	the 'ondemand' governor instead, however if you are using a laptop,
	134	PDA or even an AMD64 based computer (due to the unacceptable
	135	step-by-step latency issues between the minimum and maximum frequency
	136	transitions in the CPU) you will probably want to use this governor.
	137
	138	For details, take a look at linux/Documentation/cpu-freq.
	139
	140	If in doubt, say N.
	141
1da177e4	142	endif # CPU_FREQ