EXYNOS: bugfix on retrieving old_index from freqs.old

The policy might have been changed since last call of target().
Thus, using cpufreq_frequency_table_target(), which depends on
policy to find the corresponding index from a frequency, may return
inconsistent index for freqs.old. Thus, old_index should be
calculated not based on the current policy.

We have been observing such issue when scaling_min/max_freq were
updated and sometimes cuased system lockups deu to incorrectly
configured voltages.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/cpufreq/exynos-cpufreq.c b/drivers/cpufreq/exynos-cpufreq.c
index b243a7e..af2d81e 100644 (file)
--- a/drivers/cpufreq/exynos-cpufreq.c
+++ b/drivers/cpufreq/exynos-cpufreq.c
@@ -62,8 +62,18 @@ static int exynos_target(struct cpufreq_policy *policy,
                goto out;
        }
 
-       if (cpufreq_frequency_table_target(policy, freq_table,
-                                          freqs.old, relation, &old_index)) {
+       /*
+        * The policy max have been changed so that we cannot get proper
+        * old_index with cpufreq_frequency_table_target(). Thus, ignore
+        * policy and get the index from the raw freqeuncy table.
+        */
+       for (old_index = 0;
+               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
+               old_index++)
+               if (freq_table[old_index].frequency == freqs.old)
+                       break;
+
+       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
                ret = -EINVAL;
                goto out;
        }