• Doug Smythies's avatar
    intel_pstate: Correct rounding in busy calculation · 51d211e9
    Doug Smythies authored
    There was a mistake in the actual rounding portion this previous patch:
    f0fe3cd7 (intel_pstate: Correct rounding in busy calculation) such that
    the rounding was asymetric and incorrect.
    
    Severity: Not very serious, but can increase target pstate by one extra value.
    For real world work flows the issue should self correct (but I have no proof).
    It is the equivalent of different PID gains for positive and negative numbers.
    
    Examples:
     -3.000000 used to round to -4, rounds to -3 with this patch.
     -3.503906 used to round to -5, rounds to -4 with this patch.
    
    Fixes: f0fe3cd7 (intel_pstate: Correct rounding in busy calculation)
    Signed-off-by: default avatarDoug Smythies <dsmythies@telus.net>
    Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    51d211e9
intel_pstate.c 22.4 KB