[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: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index b735458c6e3a..563dcc82b902 100644
--- a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -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)