linux-kernel - [PATCH] intel_pstate: set BYT MSR with wrmsrl_on

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Message-Id: <1431442782-12061-1-git-send-email-joe.konno@linux.intel.com>
Date:	Tue, 12 May 2015 07:59:42 -0700
From:	Joe Konno <joe.konno@...ux.intel.com>
To:	rjw@...ysocki.net
Cc:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	viresh.kumar@...aro.org, kristen@...ux.intel.com
Subject: [PATCH] intel_pstate: set BYT MSR with wrmsrl_on_cpu()

From: Joe Konno <joe.konno@...el.com>

Commit 007bea098b86 (intel_pstate: Add setting voltage value for
baytrail P states.) introduced byt_set_pstate() with the assumption that
it would always be run by the CPU whose MSR is to be written by it.  It
turns out, however, that is not always the case in practice, so modify
byt_set_pstate() to enforce the MSR write done by it to always happen on
the right CPU.

v2: better commit message, remove For: tag

Fixes: 007bea098b86 ("intel_pstate: Add setting voltage value for
       baytrail P states.")
Signed-off-by: Joe Konno <joe.konno@...el.com>
---
 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 6414661ac1c4..c45d274a75c8 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -535,7 +535,7 @@ static void byt_set_pstate(struct cpudata *cpudata, int pstate)
 
 	val |= vid;
 
-	wrmsrl(MSR_IA32_PERF_CTL, val);
+	wrmsrl_on_cpu(cpudata->cpu, MSR_IA32_PERF_CTL, val);
 }
 
 #define BYT_BCLK_FREQS 5
-- 
2.4.0

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