i386, x86-64: show that CONFIG_HOTPLUG_CPU is required for suspend on SMP

It's not sufficiently documented that CONFIG_HOTPLUG_CPU is required for
suspend/hibernation on SMP.

Point out the non-obvious.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index c2d54b8..8770a5d 100644 (file)
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -891,7 +891,7 @@ config PHYSICAL_ALIGN
          Don't change this unless you know what you are doing.
 
 config HOTPLUG_CPU
-       bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
+       bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
        depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
        ---help---
          Say Y here to experiment with turning CPUs off and on, and to

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 145bb82..5ce9443 100644 (file)
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -428,12 +428,15 @@ config NR_CPUS
          memory in the static kernel configuration.
 
 config HOTPLUG_CPU
-       bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
+       bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
        depends on SMP && HOTPLUG && EXPERIMENTAL
        help
                Say Y here to experiment with turning CPUs off and on.  CPUs
                can be controlled through /sys/devices/system/cpu/cpu#.
-               Say N if you want to disable CPU hotplug.
+               This is also required for suspend/hibernation on SMP systems.
+
+               Say N if you want to disable CPU hotplug and don't need to
+               suspend.
 
 config ARCH_ENABLE_MEMORY_HOTPLUG
        def_bool y