On Wed, 2015-10-07 at 23:09 +0530, Viresh Kumar wrote:
[...]
> And why not fix it properly by doing this:
>
> diff --git a/drivers/cpufreq/arm_big_little.c
> b/drivers/cpufreq/arm_big_little.c
> index f1e42f8ce0fc..5b36657a76d6 100644
> --- a/drivers/cpufreq/arm_big_little.c
> +++ b/drivers/cpufreq/arm_big_little.c
> @@ -128,7 +128,7 @@ static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
> static unsigned int
> bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
> {
> - u32 new_rate, prev_rate;
> + u32 new_rate, prev_rate, target_rate;
> int ret;
> bool bLs = is_bL_switching_enabled();
>
> @@ -140,9 +140,11 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32
> new_cluster, u32 rate)
> per_cpu(physical_cluster, cpu) = new_cluster;
>
> new_rate = find_cluster_maxfreq(new_cluster);
> + target_rate = new_rate;
> new_rate = ACTUAL_FREQ(new_cluster, new_rate);
> } else {
> new_rate = rate;
> + target_rate = new_rate;
> }
>
> pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
> @@ -196,7 +198,7 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32
> new_cluster, u32 rate)
> * be reading only the cached value anyway. This needs to be removed
> * once clk core is fixed.
> */
> - if (bL_cpufreq_get_rate(cpu) != new_rate)
> + if (bL_cpufreq_get_rate(cpu) != target_rate)
> return -EIO;
> return 0;
> }
You call that a proper fix? ;-) It's comparing an 'virtual' frequency to
an 'actual' frequency.
If the real intent is to check that clk_set_rate works I would have
thought the patch below would be correct. But I didn't propose that as
it's the obvious implementation and I assumed the original patch didn't
do it that way for a reason.
diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c
index f1e42f8..59115a4 100644
--- a/drivers/cpufreq/arm_big_little.c
+++ b/drivers/cpufreq/arm_big_little.c
@@ -149,6 +149,18 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32
new_cluster, u32 rate)
__func__, cpu, old_cluster, new_cluster, new_rate);
ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
+ if (!ret) {
+ /*
+ * FIXME: clk_set_rate has to handle the case where
clk_change_rate
+ * can fail due to hardware or firmware issues. Until the clk
core
+ * layer is fixed, we can check here. In most of the cases we
will
+ * be reading only the cached value anyway. This needs to be
removed
+ * once clk core is fixed.
+ */
+ if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
+ ret = -EIO;
+ }
+
if (WARN_ON(ret)) {
pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
new_cluster);
@@ -189,15 +201,6 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32
new_cluster, u32 rate)
mutex_unlock(&cluster_lock[old_cluster]);
}
- /*
- * FIXME: clk_set_rate has to handle the case where clk_change_rate
- * can fail due to hardware or firmware issues. Until the clk core
- * layer is fixed, we can check here. In most of the cases we will
- * be reading only the cached value anyway. This needs to be removed
- * once clk core is fixed.
- */
- if (bL_cpufreq_get_rate(cpu) != new_rate)
- return -EIO;
return 0;
}
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