linux-kernel - [PATCH] [CPUFREQ] powernow-k8: Don't try to transition if the pstate is incorrect or there is no freq for it.

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Date:	Thu, 16 Jun 2011 10:28:29 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	linux-kernel@...r.kernel.org, davej@...hat.com, x86@...nel.org,
	cpufreq@...r.kernel.org, bp@...en8.de, andre.przywara@....com,
	Mark.Langsdorf@....com
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com
Subject: [PATCH] [CPUFREQ] powernow-k8: Don't try to transition if the pstate
 is incorrect or there is no freq for it. 


And as mentioned, the other patch that just deals with pstates.

>From 0f3bc30b6bc7dad62e3b77063b69df44ca9a9f8e Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Date: Wed, 15 Jun 2011 11:08:02 -0400
Subject: [PATCH] [CPUFREQ] powernow-k8: Don't try to transition if the pstate is incorrect or there is no freq for it.

This patch auguments the pstate transition code to error out
(instead of returning 0) when a incorrect pstate is provided.

It also checks whether the frequency for the pstate is
incorrect and if so errors out.

Suggested-by: Borislav Petkov <bp@...en8.de>
CC: andre.przywara@....com
CC: Mark.Langsdorf@....com
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
 drivers/cpufreq/powernow-k8.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index fe53572..047c7b11 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1103,11 +1103,15 @@ static int transition_frequency_pstate(struct powernow_k8_data *data,
 	/* get MSR index for hardware pstate transition */
 	pstate = index & HW_PSTATE_MASK;
 	if (pstate > data->max_hw_pstate)
-		return 0;
+		return -EINVAL;
+
 	freqs.old = find_khz_freq_from_pstate(data->powernow_table,
 			data->currpstate);
 	freqs.new = find_khz_freq_from_pstate(data->powernow_table, pstate);
 
+	if (freqs.new == CPUFREQ_ENTRY_INVALID)
+		return -EINVAL;
+
 	for_each_cpu(i, data->available_cores) {
 		freqs.cpu = i;
 		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
-- 
1.7.5.4

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