• Rafael J. Wysocki's avatar
    cpuidle: Consolidate disabled state checks · 99e98d3f
    Rafael J. Wysocki authored
    There are two reasons why CPU idle states may be disabled: either
    because the driver has disabled them or because they have been
    disabled by user space via sysfs.
    
    In the former case, the state's "disabled" flag is set once during
    the initialization of the driver and it is never cleared later (it
    is read-only effectively).  In the latter case, the "disable" field
    of the given state's cpuidle_state_usage struct is set and it may be
    changed via sysfs.  Thus checking whether or not an idle state has
    been disabled involves reading these two flags every time.
    
    In order to avoid the additional check of the state's "disabled" flag
    (which is effectively read-only anyway), use the value of it at the
    init time to set a (new) flag in the "disable" field of that state's
    cpuidle_state_usage structure and use the sysfs interface to
    manipulate another (new) flag in it.  This way the state is disabled
    whenever the "disable" field of its cpuidle_state_usage structure is
    nonzero, whatever the reason, and it is the only place to look into
    to check whether or not the state has been disabled.
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
    Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    99e98d3f
cpuidle.c 18.1 KB