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    SubjectRe: [PATCH] arm: platsmp: Allow secondary cpu hotplug with maxcpus=1
    On Wed, Jun 29, 2011 at 11:31:39AM -0700, Stephen Boyd wrote:
    > If an ARM system has multiple cpus in the same socket and the
    > kernel is booted with maxcpus=1, secondary cpus are possible but
    > not present due to how platform_smp_prepare_cpus() is called.
    > Fix this by always calling platform_smp_prepare_cpus() as long as
    > max_cpus is non-zero (0 means no SMP) to allow platform code to
    > decide if any non-boot cpus are present in the system. Since
    > all current platform code doesn't support physical hotplug we
    > have a situation where possible == present and thus we can
    > simply copy the possible map to the present map.
    >
    > With this patch it's possible to boot an ARM system with
    > maxcpus=1 on the command line and then hotplug in secondary cpus
    > via sysfs. This is more in line with how x86 works with maxcpus=1
    > on the command line.
    >
    > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

    Acked-by: Paul Mundt <lethal@linux-sh.org>


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