• Len Brown's avatar
    ACPI: thermal: use round_jiffies when thermal zone polling is enabled · 21bc42ab
    Len Brown authored
    Properly functioning systems do not use thermal zone polling,
    they use event-based notification.
    
    However, some users enable periodic thermal zone polling
    to work around bugs on their platforms, and at least one
    platform exists with a real _TZP that requests polling.
    
    While thermal zone polling (_TZP) is specified in units to 0.1 seconds,
    it actually has a maximum granularity of 1 second.  Thus, we can safely
    round up the _TZP timeout to occur on the next 1-second boundary.
    This will batch it with other 1-second-granularity timers in the
    system and thus potentially extend processor idle duration.
    
    Note that the same timer is used both for _TZP
    and for passive processor thermal throttling.
    We can not round up the timeout when it is used
    for passive thermal throttling.
    
    Also, we can not make this a deferrable timer,
    as temperature is just as relevant during idle
    as it is during non-idle.
    Signed-off-by: default avatarLen Brown <len.brown@intel.com>
    21bc42ab
thermal.c 37.1 KB