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From: dirk.brandewie@gmail.com
To: linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org
Cc: konrad.wilk@oracle.com, jwboyer@redhat.com,
	Dirk Brandewie <dirk.brandewie@gmail.com>,
	Dirk Brandewie <dirk.j.brandewie@intel.com>
Subject: [PATCH 1/2] cpufreq/intel_pstate: Do not load on VM that do not report max P state.
Date: Tue,  5 Mar 2013 14:15:26 -0800	[thread overview]
Message-ID: <1362521727-20666-2-git-send-email-dirk.brandewie@gmail.com> (raw)
In-Reply-To: <1362521727-20666-1-git-send-email-dirk.brandewie@gmail.com>

From: Dirk Brandewie <dirk.brandewie@gmail.com>

It seems some VMs support the P state MSRs but return zeros. Fail
gracefully if we are running in this environment.

https://bugzilla.redhat.com/show_bug.cgi?id=916833

Reported-by: jwboyer@redhat.com
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
---
 drivers/cpufreq/intel_pstate.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 096fde0..2bfd083 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -662,6 +662,9 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy)
 
 	cpu = all_cpu_data[policy->cpu];
 
+	if (!policy->cpuinfo.max_freq)
+		return -ENODEV;
+
 	intel_pstate_get_min_max(cpu, &min, &max);
 
 	limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
-- 
1.7.7.6


  reply	other threads:[~2013-03-05 22:15 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-05 22:15 [PATCH 0/2] v3.9-rc1 fixes for intel_pstate driver dirk.brandewie
2013-03-05 22:15 ` dirk.brandewie [this message]
2013-03-05 22:15 ` [PATCH 2/2] cpufreq/intel_pstate: Fix intel_pstate_init() error path dirk.brandewie
2013-03-06 13:37   ` Viresh Kumar
2013-03-06 13:37 ` [PATCH 0/2] v3.9-rc1 fixes for intel_pstate driver Viresh Kumar

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