commit 12b17c2879a2341e05e53cef1c2e97bd82ba0409 Author: John Vogel <jvogel4@stny.rr.com> Date: Wed Jul 31 16:11:24 2019 -0400 pm-utils: improve README as per request Add information about kernel config parameters needed for using pm-utils. Content provided by chinarulezzz. diff --git a/pm-utils/README b/pm-utils/README index 75ad9333..83699d66 100644 --- a/pm-utils/README +++ b/pm-utils/README @@ -5,3 +5,30 @@ README for pm-utils NOTES Read http://crux.nu/Wiki/Pm-utils for usage. + + +Kernel Configuration: + +If needed, enable the following options in the kernel configuration and recompile the +kernel: + +Power management and ACPI options ---> + <*> Suspend to RAM and standby [CONFIG_SUSPEND] + <*> Hibernation (aka 'suspend to disk') [CONFIG_HIBERNATION] + + +Suspend to RAM allows the system to enter sleep states in which main memory is +powered and thus its contents are preserved. The method cuts power to most parts of +the machine aside from the RAM. Because of the large power savings, it is advisable +for laptops to automatically enter this mode when the computer is running on +batteries and the lid is closed (or the user is inactive for some time). + +Suspend to disk (Hibernation) saves the machine's state into swap space and +completely powers off the machine. When the machine is powered on, the state is +restored. Until then, there is zero power consumption. Suspend to RAM and hibernation +are normally appropriate for portable devices such as laptops, but can be used on +workstations. The capability is not really appropriate for servers. + +To use hibernation, the kernel parameter resume=/dev/<swap_partition> has to be +used on the kernel command line (in grub.cfg). The swap partition should be at least +the size of the physical RAM on the system.