From: Ashok Raj CPU_HOTPLUG has race conditions when we use broadcast mode IPI. - First we introduced no_broadcast option (see include/asm-i386/mach-default/mach_ipi.h) - x86_64 solved it by using physical flat mode (same as bigsmp on i386) since this will not use broadcast shortcuts for IPI. - We switched to use bigsmp on i386 so that we can have same handling as x86_64, but apparently this caused an error message, if kernel was compiled without X86_GENERICARCH, X86_BIGSMP. The message "You have >8 CPUS..." which was bogus and misleading, and only indicated one of the above ARCH wasnt selected. So we do not switch to automatic bigsmp for HOTPLUG_CPU support in i386 until the other related config dependencies for SMP_SUSPEND etc can be done right. Signed-off-by: Ashok Raj Signed-off-by: Andrew Morton --- arch/i386/Kconfig | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) diff -puN arch/i386/Kconfig~enable-x86_pc-for-hotplug_cpu arch/i386/Kconfig --- 25/arch/i386/Kconfig~enable-x86_pc-for-hotplug_cpu Wed Apr 26 14:33:39 2006 +++ 25-akpm/arch/i386/Kconfig Wed Apr 26 14:33:39 2006 @@ -756,7 +756,7 @@ config PHYSICAL_START config HOTPLUG_CPU bool "Support for hot-pluggable CPUs (EXPERIMENTAL)" - depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER && !X86_PC + depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER ---help--- Say Y here to experiment with turning CPUs off and on. CPUs can be controlled through /sys/devices/system/cpu. _