| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.13 118/172] intel_pstate: Use LFM bus ratio as min ratio/P state | Date | Tue, 4 Mar 2014 12:03:22 -0800 |
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3.13-stable review patch. If anyone has any objections, please let me know.
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From: Dirk Brandewie <dirk.j.brandewie@intel.com>
commit 4042e7570cff740460b75c6fc604c629621d3dd2 upstream.
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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/cpufreq/intel_pstate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -348,7 +348,7 @@ 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)
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