intel_pstate: Use LFM bus ratio as min ratio/P state

LFM (max efficiency ratio) is the max frequency at minimum voltage
supported by the processor.  Using LFM as the minimum P state
increases performmance without affecting power. By not using P states
below LFM we avoid using P states that are less power efficient.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Cc: 3.13+ <stable@vger.kernel.org> # 3.13+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index c788abf1c457cea63c1b60b7bbff637e5b303228..deb04cc64ba12b7d0b2a5ca6390c51542561fb61 100644 (file)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -357,7 +357,7 @@ static int byt_get_min_pstate(void)
 {
        u64 value;
        rdmsrl(BYT_RATIOS, value);
-       return value & 0xFF;
+       return (value >> 8) & 0xFF;
 }
 
 static int byt_get_max_pstate(void)