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Commit 8edc59d9 authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Dave Jones
Browse files

[CPUFREQ] Bug fix for acpi-cpufreq and cpufreq_stats oops on frequency change notification 

Fixes the oops in cpufreq_stats with acpi_cpufreq driver.  The issue was
that the frequency was reported as 0 in acpi-cpufreq.c.  The bug is due to
different indicies for freq_table and ACPI perf table.

Also adds a check in cpufreq_stats to check for error return from
freq_table_get_index() and avoid using the error return value.

Patch fixes the issue reported at
http://www.ussg.iu.edu/hypermail/linux/kernel/0611.2/0629.html
and also other similar issue here
http://bugme.osdl.org/show_bug.cgi?id=7383

 comment 53

Signed-off-by: default avatarDhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 917325d3

arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

+5 −4
Original line number Diff line number Diff line
@@ -373,8 +373,8 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy, 
	cpumask_t online_policy_cpus;

	struct drv_cmd cmd;

	unsigned int msr;

	unsigned int next_state = 0;

	unsigned int next_perf_state = 0;

	unsigned int next_state = 0; /* Index into freq_table */

	unsigned int next_perf_state = 0; /* Index into perf table */

	unsigned int i;

	int result = 0;
@@ -439,8 +439,8 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy, 
	else

		cpu_set(policy->cpu, cmd.mask);



	freqs.old = data->freq_table[perf->state].frequency;

	freqs.new = data->freq_table[next_perf_state].frequency;

	freqs.old = perf->states[perf->state].core_frequency * 1000;

	freqs.new = data->freq_table[next_state].frequency;

	for_each_cpu_mask(i, cmd.mask) {

		freqs.cpu = i;

		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
@@ -677,6 +677,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) 
		valid_states++;

	}

	data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;

	perf->state = 0;



	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);

	if (result)

drivers/cpufreq/cpufreq_stats.c

+4 −0
Original line number Diff line number Diff line
@@ -285,6 +285,7 @@ cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val, 
	stat = cpufreq_stats_table[freq->cpu];

	if (!stat)

		return 0;



	old_index = freq_table_get_index(stat, freq->old);

	new_index = freq_table_get_index(stat, freq->new);
@@ -292,6 +293,9 @@ cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val, 
	if (old_index == new_index)

		return 0;



	if (old_index == -1 || new_index == -1)

		return 0;



	spin_lock(&cpufreq_stats_lock);

	stat->last_index = new_index;

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS