From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dirk Brandewie , "Rafael J. Wysocki" 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 Message-Id: <20140304200303.492201822@linuxfoundation.org> In-Reply-To: <20140304200259.626667112@linuxfoundation.org> References: <20140304200259.626667112@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dirk Brandewie 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 Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- 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)