linux-kernel - [PATCH 3.14 211/228] intel_pstate: remove setting P state to MAX on init

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Message-Id: <20140604232354.827268316@linuxfoundation.org>
Date:	Wed,  4 Jun 2014 16:24:00 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Patrick Marlier <patrick.marlier@...il.com>,
	Dirk Brandewie <dirk.j.brandewie@...el.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 3.14 211/228] intel_pstate: remove setting P state to MAX on init

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dirk Brandewie <dirk.j.brandewie@...el.com>

commit d40a63c45b506b0681918d7c62a15cc9d48c8681 upstream.

Setting the P state of the core to max at init time is a hold over
from early implementation of intel_pstate where intel_pstate disabled
cpufreq and loaded VERY early in the boot sequence.  This was to
ensure that intel_pstate did not affect boot time. This in not needed
now that intel_pstate is a cpufreq driver.

Removing this covers the case where a CPU has gone through a manual
CPU offline/online cycle and the P state is set to MAX on init and the
CPU immediately goes idle.  Due to HW coordination the P state request
on the idle CPU will drag all cores to MAX P state until the load is
reevaluated when to core goes non-idle.

Reported-by: Patrick Marlier <patrick.marlier@...il.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@...el.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/cpufreq/intel_pstate.c |   13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -555,12 +555,7 @@ static void intel_pstate_get_cpu_pstates

 	if (pstate_funcs.get_vid)
 		pstate_funcs.get_vid(cpu);
-
-	/*
-	 * goto max pstate so we don't slow up boot if we are built-in if we are
-	 * a module we will take care of it during normal operation
-	 */
-	intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
+	intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
 }

 static inline void intel_pstate_calc_busy(struct cpudata *cpu,
@@ -706,11 +701,6 @@ static int intel_pstate_init_cpu(unsigne
 	cpu = all_cpu_data[cpunum];

 	intel_pstate_get_cpu_pstates(cpu);
-	if (!cpu->pstate.current_pstate) {
-		all_cpu_data[cpunum] = NULL;
-		kfree(cpu);
-		return -ENODATA;
-	}

 	cpu->cpu = cpunum;

@@ -721,7 +711,6 @@ static int intel_pstate_init_cpu(unsigne
 	cpu->timer.expires = jiffies + HZ/100;
 	intel_pstate_busy_pid_reset(cpu);
 	intel_pstate_sample(cpu);
-	intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);

 	add_timer_on(&cpu->timer, cpunum);

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