[PATCH v2] intel_pstate: Use LFM bus ratio as min ratio/P state

From: dirk . brandewie
Date: Wed Feb 19 2014 - 13:36:18 EST


From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>

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@xxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index b80c03d..ff45ce1 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -356,7 +356,7 @@ 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)
--
1.8.3.1

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