Right, thanks for the file. Here's the patch.
--- omap2plus-cpufreq.c~ 2011-06-24 15:50:32.000000000 +0100
+++ omap2plus-cpufreq.c 2011-06-24 16:00:08.000000000 +0100
@@ -44,6 +44,16 @@
static char *mpu_clk_name;
static struct device *mpu_dev;
+#ifdef CONFIG_SMP
+struct lpj_info {
+ unsigned long ref;
+ unsigned int freq;
+};
+
+static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
+static struct lpj_info global_lpj_ref;
+#endif
+
static int omap_verify_speed(struct cpufreq_policy *policy)
{
if (!freq_table)
@@ -109,14 +119,25 @@
freqs.new = omap_getspeed(policy->cpu);
#ifdef CONFIG_SMP
- /* Adjust jiffies before transition */
+ /* Adjust per-cpu loops_per_jiffy before transition */
for_each_cpu(i, policy->cpus) {
- unsigned long lpj = per_cpu(cpu_data, i).loops_per_jiffy;
-
- per_cpu(cpu_data, i).loops_per_jiffy = cpufreq_scale(lpj,
- freqs.old,
- freqs.new);
+ struct lpj_info *lpj = &per_cpu(lpj_ref, i);
+ if (!lpj->freq) {
+ lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
+ lpj->freq = freqs.old;
+ }
+
+ per_cpu(cpu_data, i).loops_per_jiffy =
+ cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
+ }
+
+ /* And don't forget to adjust the global one */
+ if (!global_lpj_ref.freq) {
+ global_lpj_ref.ref = loops_per_jiffy;
+ global_lpj_ref.freq = freqs.old;
}
+ loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
+ freqs.new);
#endif
/* Notify transitions */
Notice how we adjust _both_ the per-cpu loops_per_jiffy, and that we
adjust them with reference to the initial values.
If you adjust lpj with reference to the last, then you _will_ build up
a progressively bigger and bigger error in the value over time.
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