ThinkWiki - User contributions [en]

How to make ACPI work

2008-10-20T08:14:22Z

Arteme: /* Backlight problems with post-2.6.26 kernels */ Fixed the note

==General==
First, simply try using the power management features of Linux on your computer. Tell Linux to suspend (System > Preferences > Power Management in Gnome). Try closing the lid. ACPI may already work.

===Update BIOS===
ACPI requires a relatively new BIOS version. In particular, if you get the message,
ACPI: Could not use ECDT
during startup, you probably need a [[BIOS Upgrade]]. For example, a BIOS upgrade from version 1.02 to 1.10 was all that was needed for ACPI to start working on an A31 2652 running Red Hat Enterprise Linux 5 (CentOS 5).

===Kernel configuration===
Many Kernel 2.6 distributions like Red Hat Enterprise Linux 5 (Centos 5) have ACPI built in and ready to go. If not, you must enable ACPI support in your kernel.

To do this open your kernel config and enable ACPI Power Management:
:{{kernelconf|CONFIG_PM|<*>|Power Management support|Power management options|||}}
:{{kernelconf|CONFIG_ACPI|<*>|ACPI Support|Power management options|||}}

You'd most likely want to enable the following ACPI options:
:{{kernelconf|CONFIG_SUSPEND|<*>|Suspend to RAM and standby|Power management options|||}}
:{{kernelconf|CONFIG_ACPI_AC|<*>|AC Adapter|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BATTERY|<*>|Battery|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BUTTON|<*>|Button|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_FAN|<*>|Fan|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_PROCESSOR|<*>|Processor|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_THERMAL|<*>|Thermal Zone|ACPI|Power management options||}}

If you prefer editing your {{path|.config}} file directly, you should set at least the following variables:
CONFIG_PM=y
CONFIG_ACPI=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_BLACKLIRG_YEAR=0
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y

Then recompile your kernel.

{{HINT| ACPI SLEEP States option did only show up for me after patching [[Software Suspend 2]] into the kernel. With a vanilla 2.6.17 kernel, one must enable CONFIG_SMP and CONFIG_HOTPLUG_CPU for the option to appear, cf. [http://bugs.debian.org/383059 Debian bug #383059] .
(This should be fixed in 2.6.23, there are new CONFIG_SUSPEND and CONFIG_HIBERNATION config options)}}

===Kernel boot parameters===
Many ThinkPads have been hit by a recent (kernel 2.6.16) change to ACPI4Linux that changed the default means of accessing the ACPI Embedded Controller as a way to shake out underlying bugs in the EC access code. If your ThinkPad fails to resume properly (a blinking Sleep light on resume that doesn't go away, or a hang when trying to suspend/standby a second time), adding {{bootparm|ec_intr|0}} to your kernel command line may help.

===IBM specific ACPI driver===

====Pre-2.6.22====

Unfortunately, special drivers for ACPI on ThinkPads were not included with kernels prior 2.6.10. So you'll have to compile one yourself or get it as precompiled module for your kernel.

You have the choice between [[thinkpad-acpi]] and [[ibm-acpi]], with the latter being the recommended one.

If you use a post-2.6.10 kernel and you want to use [[ibm-acpi]], it is recommended to look on its projects page for a possibly newer version.

====Post-2.6.22====

If you are using kernel version 2.6.22 and higher, you have only one choce, [[ibm-acpi]], which has been renamed to '''thinkpad-acpi'''.

{{HINT|Generally it is a good idea to read the README included with the driver.}}

===Backlight problems with post-2.6.26 kernels===

According to [[http://www.nabble.com/T61-Brightness-keys-with-2.6.26-not-working-(NVIDIA)-td18577619.html this thread]], users with 2.6.26 kernel and higher may experience problems with ThinkPad backlight contols ('''Fn+Home''', '''Fn+End''' on T61). The symptoms are:
* backlight brightness controls do not work;
* Using '''acpi-listen''' command, there is no reaction for '''brightness down''' button, but '''brightenss up''' gives:
ibm/hotkey HKEY 00000080 00001010

The solution is that one needs to enable `CONFIG_VIDEO_OUTPUT_CONTROL`:
Device Drivers --->
Graphics Support --->
<*> Lowlevel video output switch controls

Subsequently one should enable 'CONFIG_ACPI_VIDEO':
Power Management Options --->
[*] ACPI (Advanced Configuration and Power Interface) Support --->
<*> Video

{{NOTE|Without `CONFIG_VIDEO_OUTPUT_CONTROL` enabled, one will not be able to enable `CONFIG_ACPI_VIDEO` in menuconfig or similar interface as the option will remain hidden}}

===ACPI daemon===
Also you'll need to install [[acpid]], if it isn't present on your system. [[acpid]] is a daemon that handles the ACPI events generated by the system. Read [[How to configure acpid]].

==Screen blanking (Standby)==
Make sure you have
Option "DPMS"
in the Monitor section of your {{path|/etc/X11/XF86Config}} or {{path|/etc/X11/xorg.conf}}.

Running {{cmduser|xset +dpms}} and then {{cmduser|xset dpms force off}} will turn off the backlight on a laptop screen.<br />

Note that this may not work in combination with {{cmduser|echo -n "mem" > /sys/power/state}} because switching to console causes the backlight to come back on before sleeping.

==Suspend to RAM (Sleep)==
ACPI Sleep/suspend-to-ram with recent 2.6.x kernels usually works fine. Have a look at the [[How to configure acpid|acpid configuration HOWTO]]. It includes a specific example for going to sleep on lid close.

For Troubleshooting, look at the [[Problems with ACPI suspend-to-ram|Problems with ACPI suspend-to-ram page]].

==Suspend to disk (Hibernate)==
There are two drivers for this available:
* [[swsusp]], which is in the kernel and
* [[Software Suspend 2]] which is more feature rich, but not yet in the kernel, so you have to patch it in yourself.

Both are reported to work fine as long as you use open-source graphic drivers. A comparison of the features can be found on [http://softwaresuspend.berlios.de/features.html this page].

Just in case you are in doubt...yes, it is safe in both cases to use the same swap partition as active swap and as suspend partition.

See the according drivers page for instructions.

==ThinkPads on which it is recommended to use ACPI==
*ThinkPad {{770X}}, {{770Z}}
*ThinkPad {{A20m}}, {{A20p}}, {{A20m}}, {{A20p}}, {{A21e}}, {{A21m}}, {{A21p}}, {{A22e}}, {{A22m}}, {{A22p}}, {{A30}}, {{A30p}}, {{A31}}, {{A31p}}
*ThinkPad {{G40}}, {{G41}}
*ThinkPad {{R30}}, {{R31}}, {{R32}}, {{R40}}, {{R40e}}, {{R50}}, {{R50e}}, {{R50p}}, {{R51}}, {{R52}}, {{R60}}
*ThinkPad {{T22}}, {{T23}}, {{T30}}, {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}, {{T43}}, {{T43p}}, {{T61}}
*ThinkPad {{X20}}, {{X21}}, {{X22}}, {{X23}}, {{X24}}, {{X30}}, {{X31}}, {{X32}}, {{X40}}, {{X41}}, {{X41T}}
*ThinkPad {{Z60t}}, {{Z60m}}, {{Z61m}}
*ThinkPad {{X60s}}
*ThinkPad {{TransNote}}
*ThinkPad {{T20}} and {{T21}} have old ACPI implementations, but there have been some reports of using ACPI successfully on these models with Ubuntu and Mandriva in particular. Check the related pages about installing Linux on these models for details.

How to make ACPI work

2008-10-20T08:13:35Z

Arteme: /* Backlight problems with post-2.6.26 kernels */ Finished the writeup

==General==
First, simply try using the power management features of Linux on your computer. Tell Linux to suspend (System > Preferences > Power Management in Gnome). Try closing the lid. ACPI may already work.

===Update BIOS===
ACPI requires a relatively new BIOS version. In particular, if you get the message,
ACPI: Could not use ECDT
during startup, you probably need a [[BIOS Upgrade]]. For example, a BIOS upgrade from version 1.02 to 1.10 was all that was needed for ACPI to start working on an A31 2652 running Red Hat Enterprise Linux 5 (CentOS 5).

===Kernel configuration===
Many Kernel 2.6 distributions like Red Hat Enterprise Linux 5 (Centos 5) have ACPI built in and ready to go. If not, you must enable ACPI support in your kernel.

To do this open your kernel config and enable ACPI Power Management:
:{{kernelconf|CONFIG_PM|<*>|Power Management support|Power management options|||}}
:{{kernelconf|CONFIG_ACPI|<*>|ACPI Support|Power management options|||}}

You'd most likely want to enable the following ACPI options:
:{{kernelconf|CONFIG_SUSPEND|<*>|Suspend to RAM and standby|Power management options|||}}
:{{kernelconf|CONFIG_ACPI_AC|<*>|AC Adapter|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BATTERY|<*>|Battery|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BUTTON|<*>|Button|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_FAN|<*>|Fan|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_PROCESSOR|<*>|Processor|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_THERMAL|<*>|Thermal Zone|ACPI|Power management options||}}

If you prefer editing your {{path|.config}} file directly, you should set at least the following variables:
CONFIG_PM=y
CONFIG_ACPI=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_BLACKLIRG_YEAR=0
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y

Then recompile your kernel.

{{HINT| ACPI SLEEP States option did only show up for me after patching [[Software Suspend 2]] into the kernel. With a vanilla 2.6.17 kernel, one must enable CONFIG_SMP and CONFIG_HOTPLUG_CPU for the option to appear, cf. [http://bugs.debian.org/383059 Debian bug #383059] .
(This should be fixed in 2.6.23, there are new CONFIG_SUSPEND and CONFIG_HIBERNATION config options)}}

===Kernel boot parameters===
Many ThinkPads have been hit by a recent (kernel 2.6.16) change to ACPI4Linux that changed the default means of accessing the ACPI Embedded Controller as a way to shake out underlying bugs in the EC access code. If your ThinkPad fails to resume properly (a blinking Sleep light on resume that doesn't go away, or a hang when trying to suspend/standby a second time), adding {{bootparm|ec_intr|0}} to your kernel command line may help.

===IBM specific ACPI driver===

====Pre-2.6.22====

Unfortunately, special drivers for ACPI on ThinkPads were not included with kernels prior 2.6.10. So you'll have to compile one yourself or get it as precompiled module for your kernel.

You have the choice between [[thinkpad-acpi]] and [[ibm-acpi]], with the latter being the recommended one.

If you use a post-2.6.10 kernel and you want to use [[ibm-acpi]], it is recommended to look on its projects page for a possibly newer version.

====Post-2.6.22====

If you are using kernel version 2.6.22 and higher, you have only one choce, [[ibm-acpi]], which has been renamed to '''thinkpad-acpi'''.

{{HINT|Generally it is a good idea to read the README included with the driver.}}

===Backlight problems with post-2.6.26 kernels===

According to [[http://www.nabble.com/T61-Brightness-keys-with-2.6.26-not-working-(NVIDIA)-td18577619.html this thread]], users with 2.6.26 kernel and higher may experience problems with ThinkPad backlight contols ('''Fn+Home''', '''Fn+End''' on T61). The symptoms are:
* backlight brightness controls do not work;
* Using '''acpi-listen''' command, there is no reaction for '''brightness down''' button, but '''brightenss up''' gives:
ibm/hotkey HKEY 00000080 00001010

The solution is that one needs to enable `CONFIG_VIDEO_OUTPUT_CONTROL`:
Device Drivers --->
Graphics Support --->
<*> Lowlevel video output switch controls

Subsequently one should enable 'CONFIG_ACPI_VIDEO':
Power Management Options --->
[*] ACPI (Advanced Configuration and Power Interface) Support --->
<*> Video

{{Note|Without `CONFIG_VIDEO_OUTPUT_CONTROL` enabled, one will not be able to enable `CONFIG_ACPI_VIDEO` in menuconfig or similar interface as the option will remain hidden}}

===ACPI daemon===
Also you'll need to install [[acpid]], if it isn't present on your system. [[acpid]] is a daemon that handles the ACPI events generated by the system. Read [[How to configure acpid]].

==Screen blanking (Standby)==
Make sure you have
Option "DPMS"
in the Monitor section of your {{path|/etc/X11/XF86Config}} or {{path|/etc/X11/xorg.conf}}.

Running {{cmduser|xset +dpms}} and then {{cmduser|xset dpms force off}} will turn off the backlight on a laptop screen.<br />

Note that this may not work in combination with {{cmduser|echo -n "mem" > /sys/power/state}} because switching to console causes the backlight to come back on before sleeping.

==Suspend to RAM (Sleep)==
ACPI Sleep/suspend-to-ram with recent 2.6.x kernels usually works fine. Have a look at the [[How to configure acpid|acpid configuration HOWTO]]. It includes a specific example for going to sleep on lid close.

For Troubleshooting, look at the [[Problems with ACPI suspend-to-ram|Problems with ACPI suspend-to-ram page]].

==Suspend to disk (Hibernate)==
There are two drivers for this available:
* [[swsusp]], which is in the kernel and
* [[Software Suspend 2]] which is more feature rich, but not yet in the kernel, so you have to patch it in yourself.

Both are reported to work fine as long as you use open-source graphic drivers. A comparison of the features can be found on [http://softwaresuspend.berlios.de/features.html this page].

Just in case you are in doubt...yes, it is safe in both cases to use the same swap partition as active swap and as suspend partition.

See the according drivers page for instructions.

==ThinkPads on which it is recommended to use ACPI==
*ThinkPad {{770X}}, {{770Z}}
*ThinkPad {{A20m}}, {{A20p}}, {{A20m}}, {{A20p}}, {{A21e}}, {{A21m}}, {{A21p}}, {{A22e}}, {{A22m}}, {{A22p}}, {{A30}}, {{A30p}}, {{A31}}, {{A31p}}
*ThinkPad {{G40}}, {{G41}}
*ThinkPad {{R30}}, {{R31}}, {{R32}}, {{R40}}, {{R40e}}, {{R50}}, {{R50e}}, {{R50p}}, {{R51}}, {{R52}}, {{R60}}
*ThinkPad {{T22}}, {{T23}}, {{T30}}, {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}, {{T43}}, {{T43p}}, {{T61}}
*ThinkPad {{X20}}, {{X21}}, {{X22}}, {{X23}}, {{X24}}, {{X30}}, {{X31}}, {{X32}}, {{X40}}, {{X41}}, {{X41T}}
*ThinkPad {{Z60t}}, {{Z60m}}, {{Z61m}}
*ThinkPad {{X60s}}
*ThinkPad {{TransNote}}
*ThinkPad {{T20}} and {{T21}} have old ACPI implementations, but there have been some reports of using ACPI successfully on these models with Ubuntu and Mandriva in particular. Check the related pages about installing Linux on these models for details.

How to make ACPI work

2008-10-20T08:02:15Z

Arteme: Added a section about backlight problems in 2.6.26

==General==
First, simply try using the power management features of Linux on your computer. Tell Linux to suspend (System > Preferences > Power Management in Gnome). Try closing the lid. ACPI may already work.

===Update BIOS===
ACPI requires a relatively new BIOS version. In particular, if you get the message,
ACPI: Could not use ECDT
during startup, you probably need a [[BIOS Upgrade]]. For example, a BIOS upgrade from version 1.02 to 1.10 was all that was needed for ACPI to start working on an A31 2652 running Red Hat Enterprise Linux 5 (CentOS 5).

===Kernel configuration===
Many Kernel 2.6 distributions like Red Hat Enterprise Linux 5 (Centos 5) have ACPI built in and ready to go. If not, you must enable ACPI support in your kernel.

To do this open your kernel config and enable ACPI Power Management:
:{{kernelconf|CONFIG_PM|<*>|Power Management support|Power management options|||}}
:{{kernelconf|CONFIG_ACPI|<*>|ACPI Support|Power management options|||}}

You'd most likely want to enable the following ACPI options:
:{{kernelconf|CONFIG_SUSPEND|<*>|Suspend to RAM and standby|Power management options|||}}
:{{kernelconf|CONFIG_ACPI_AC|<*>|AC Adapter|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BATTERY|<*>|Battery|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BUTTON|<*>|Button|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_FAN|<*>|Fan|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_PROCESSOR|<*>|Processor|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_THERMAL|<*>|Thermal Zone|ACPI|Power management options||}}

If you prefer editing your {{path|.config}} file directly, you should set at least the following variables:
CONFIG_PM=y
CONFIG_ACPI=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_BLACKLIRG_YEAR=0
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y

Then recompile your kernel.

{{HINT| ACPI SLEEP States option did only show up for me after patching [[Software Suspend 2]] into the kernel. With a vanilla 2.6.17 kernel, one must enable CONFIG_SMP and CONFIG_HOTPLUG_CPU for the option to appear, cf. [http://bugs.debian.org/383059 Debian bug #383059] .
(This should be fixed in 2.6.23, there are new CONFIG_SUSPEND and CONFIG_HIBERNATION config options)}}

===Kernel boot parameters===
Many ThinkPads have been hit by a recent (kernel 2.6.16) change to ACPI4Linux that changed the default means of accessing the ACPI Embedded Controller as a way to shake out underlying bugs in the EC access code. If your ThinkPad fails to resume properly (a blinking Sleep light on resume that doesn't go away, or a hang when trying to suspend/standby a second time), adding {{bootparm|ec_intr|0}} to your kernel command line may help.

===IBM specific ACPI driver===

====Pre-2.6.22====

Unfortunately, special drivers for ACPI on ThinkPads were not included with kernels prior 2.6.10. So you'll have to compile one yourself or get it as precompiled module for your kernel.

You have the choice between [[thinkpad-acpi]] and [[ibm-acpi]], with the latter being the recommended one.

If you use a post-2.6.10 kernel and you want to use [[ibm-acpi]], it is recommended to look on its projects page for a possibly newer version.

====Post-2.6.22====

If you are using kernel version 2.6.22 and higher, you have only one choce, [[ibm-acpi]], which has been renamed to '''thinkpad-acpi'''.

{{HINT|Generally it is a good idea to read the README included with the driver.}}

===Backlight problems with post-2.6.26 kernels===

According to [[http://www.nabble.com/T61-Brightness-keys-with-2.6.26-not-working-(NVIDIA)-td18577619.html]], users with 2.6.26 kernel and higher may experience problems with ThinkPad backlight contols ('''Fn+Home''', '''Fn+End''' on T61). The symptoms are:
* backlight brightness controls do not work;
* Using '''acpi-listen''' command, there is no reaction for '''brightness down''' button, but '''brightenss up''' gives:
ibm/hotkey HKEY 00000080 00001010

===ACPI daemon===
Also you'll need to install [[acpid]], if it isn't present on your system. [[acpid]] is a daemon that handles the ACPI events generated by the system. Read [[How to configure acpid]].

==Screen blanking (Standby)==
Make sure you have
Option "DPMS"
in the Monitor section of your {{path|/etc/X11/XF86Config}} or {{path|/etc/X11/xorg.conf}}.

Running {{cmduser|xset +dpms}} and then {{cmduser|xset dpms force off}} will turn off the backlight on a laptop screen.<br />

Note that this may not work in combination with {{cmduser|echo -n "mem" > /sys/power/state}} because switching to console causes the backlight to come back on before sleeping.

==Suspend to RAM (Sleep)==
ACPI Sleep/suspend-to-ram with recent 2.6.x kernels usually works fine. Have a look at the [[How to configure acpid|acpid configuration HOWTO]]. It includes a specific example for going to sleep on lid close.

For Troubleshooting, look at the [[Problems with ACPI suspend-to-ram|Problems with ACPI suspend-to-ram page]].

==Suspend to disk (Hibernate)==
There are two drivers for this available:
* [[swsusp]], which is in the kernel and
* [[Software Suspend 2]] which is more feature rich, but not yet in the kernel, so you have to patch it in yourself.

Both are reported to work fine as long as you use open-source graphic drivers. A comparison of the features can be found on [http://softwaresuspend.berlios.de/features.html this page].

Just in case you are in doubt...yes, it is safe in both cases to use the same swap partition as active swap and as suspend partition.

See the according drivers page for instructions.

==ThinkPads on which it is recommended to use ACPI==
*ThinkPad {{770X}}, {{770Z}}
*ThinkPad {{A20m}}, {{A20p}}, {{A20m}}, {{A20p}}, {{A21e}}, {{A21m}}, {{A21p}}, {{A22e}}, {{A22m}}, {{A22p}}, {{A30}}, {{A30p}}, {{A31}}, {{A31p}}
*ThinkPad {{G40}}, {{G41}}
*ThinkPad {{R30}}, {{R31}}, {{R32}}, {{R40}}, {{R40e}}, {{R50}}, {{R50e}}, {{R50p}}, {{R51}}, {{R52}}, {{R60}}
*ThinkPad {{T22}}, {{T23}}, {{T30}}, {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}, {{T43}}, {{T43p}}, {{T61}}
*ThinkPad {{X20}}, {{X21}}, {{X22}}, {{X23}}, {{X24}}, {{X30}}, {{X31}}, {{X32}}, {{X40}}, {{X41}}, {{X41T}}
*ThinkPad {{Z60t}}, {{Z60m}}, {{Z61m}}
*ThinkPad {{X60s}}
*ThinkPad {{TransNote}}
*ThinkPad {{T20}} and {{T21}} have old ACPI implementations, but there have been some reports of using ACPI successfully on these models with Ubuntu and Mandriva in particular. Check the related pages about installing Linux on these models for details.

How to make ACPI work

2008-10-20T07:46:46Z

Arteme: /* IBM specific ACPI driver */ Added a note about ibm-acpi and thinkpad-acpi relation in 2.6.22+

==General==
First, simply try using the power management features of Linux on your computer. Tell Linux to suspend (System > Preferences > Power Management in Gnome). Try closing the lid. ACPI may already work.

===Update BIOS===
ACPI requires a relatively new BIOS version. In particular, if you get the message,
ACPI: Could not use ECDT
during startup, you probably need a [[BIOS Upgrade]]. For example, a BIOS upgrade from version 1.02 to 1.10 was all that was needed for ACPI to start working on an A31 2652 running Red Hat Enterprise Linux 5 (CentOS 5).

===Kernel configuration===
Many Kernel 2.6 distributions like Red Hat Enterprise Linux 5 (Centos 5) have ACPI built in and ready to go. If not, you must enable ACPI support in your kernel.

To do this open your kernel config and enable ACPI Power Management:
:{{kernelconf|CONFIG_PM|<*>|Power Management support|Power management options|||}}
:{{kernelconf|CONFIG_ACPI|<*>|ACPI Support|Power management options|||}}

You'd most likely want to enable the following ACPI options:
:{{kernelconf|CONFIG_SUSPEND|<*>|Suspend to RAM and standby|Power management options|||}}
:{{kernelconf|CONFIG_ACPI_AC|<*>|AC Adapter|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BATTERY|<*>|Battery|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_BUTTON|<*>|Button|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_FAN|<*>|Fan|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_PROCESSOR|<*>|Processor|ACPI|Power management options||}}
:{{kernelconf|CONFIG_ACPI_THERMAL|<*>|Thermal Zone|ACPI|Power management options||}}

If you prefer editing your {{path|.config}} file directly, you should set at least the following variables:
CONFIG_PM=y
CONFIG_ACPI=y
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
CONFIG_ACPI_FAN=y
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_THERMAL=y
CONFIG_ACPI_BLACKLIRG_YEAR=0
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y

Then recompile your kernel.

{{HINT| ACPI SLEEP States option did only show up for me after patching [[Software Suspend 2]] into the kernel. With a vanilla 2.6.17 kernel, one must enable CONFIG_SMP and CONFIG_HOTPLUG_CPU for the option to appear, cf. [http://bugs.debian.org/383059 Debian bug #383059] .
(This should be fixed in 2.6.23, there are new CONFIG_SUSPEND and CONFIG_HIBERNATION config options)}}

===Kernel boot parameters===
Many ThinkPads have been hit by a recent (kernel 2.6.16) change to ACPI4Linux that changed the default means of accessing the ACPI Embedded Controller as a way to shake out underlying bugs in the EC access code. If your ThinkPad fails to resume properly (a blinking Sleep light on resume that doesn't go away, or a hang when trying to suspend/standby a second time), adding {{bootparm|ec_intr|0}} to your kernel command line may help.

===IBM specific ACPI driver===

====Pre-2.6.22====

Unfortunately, special drivers for ACPI on ThinkPads were not included with kernels prior 2.6.10. So you'll have to compile one yourself or get it as precompiled module for your kernel.

You have the choice between [[thinkpad-acpi]] and [[ibm-acpi]], with the latter being the recommended one.

If you use a post-2.6.10 kernel and you want to use [[ibm-acpi]], it is recommended to look on its projects page for a possibly newer version.

====Post-2.6.22====

If you are using kernel version 2.6.22 and higher, you have only one choce, [[ibm-acpi]], which has been renamed to '''thinkpad-acpi'''.

{{HINT|Generally it is a good idea to read the README included with the driver.}}

===ACPI daemon===
Also you'll need to install [[acpid]], if it isn't present on your system. [[acpid]] is a daemon that handles the ACPI events generated by the system. Read [[How to configure acpid]].

==Screen blanking (Standby)==
Make sure you have
Option "DPMS"
in the Monitor section of your {{path|/etc/X11/XF86Config}} or {{path|/etc/X11/xorg.conf}}.

Running {{cmduser|xset +dpms}} and then {{cmduser|xset dpms force off}} will turn off the backlight on a laptop screen.<br />

Note that this may not work in combination with {{cmduser|echo -n "mem" > /sys/power/state}} because switching to console causes the backlight to come back on before sleeping.

==Suspend to RAM (Sleep)==
ACPI Sleep/suspend-to-ram with recent 2.6.x kernels usually works fine. Have a look at the [[How to configure acpid|acpid configuration HOWTO]]. It includes a specific example for going to sleep on lid close.

For Troubleshooting, look at the [[Problems with ACPI suspend-to-ram|Problems with ACPI suspend-to-ram page]].

==Suspend to disk (Hibernate)==
There are two drivers for this available:
* [[swsusp]], which is in the kernel and
* [[Software Suspend 2]] which is more feature rich, but not yet in the kernel, so you have to patch it in yourself.

Both are reported to work fine as long as you use open-source graphic drivers. A comparison of the features can be found on [http://softwaresuspend.berlios.de/features.html this page].

Just in case you are in doubt...yes, it is safe in both cases to use the same swap partition as active swap and as suspend partition.

See the according drivers page for instructions.

==ThinkPads on which it is recommended to use ACPI==
*ThinkPad {{770X}}, {{770Z}}
*ThinkPad {{A20m}}, {{A20p}}, {{A20m}}, {{A20p}}, {{A21e}}, {{A21m}}, {{A21p}}, {{A22e}}, {{A22m}}, {{A22p}}, {{A30}}, {{A30p}}, {{A31}}, {{A31p}}
*ThinkPad {{G40}}, {{G41}}
*ThinkPad {{R30}}, {{R31}}, {{R32}}, {{R40}}, {{R40e}}, {{R50}}, {{R50e}}, {{R50p}}, {{R51}}, {{R52}}, {{R60}}
*ThinkPad {{T22}}, {{T23}}, {{T30}}, {{T40}}, {{T40p}}, {{T41}}, {{T41p}}, {{T42}}, {{T42p}}, {{T43}}, {{T43p}}, {{T61}}
*ThinkPad {{X20}}, {{X21}}, {{X22}}, {{X23}}, {{X24}}, {{X30}}, {{X31}}, {{X32}}, {{X40}}, {{X41}}, {{X41T}}
*ThinkPad {{Z60t}}, {{Z60m}}, {{Z61m}}
*ThinkPad {{X60s}}
*ThinkPad {{TransNote}}
*ThinkPad {{T20}} and {{T21}} have old ACPI implementations, but there have been some reports of using ACPI successfully on these models with Ubuntu and Mandriva in particular. Check the related pages about installing Linux on these models for details.