On Fri, Oct 24, 2014 at 11:53:05AM +0200, Ulf Hansson wrote:

On 23 October 2014 16:37, Grygorii Strashko [off-list ref] wrote:

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Hi Ulf,

On 10/23/2014 11:11 AM, Ulf Hansson wrote:

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On 22 October 2014 17:44, Geert Uytterhoeven [off-list ref] wrote:

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On Wed, Oct 22, 2014 at 5:28 PM, Ulf Hansson [off-list ref] wrote:

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On 22 October 2014 17:09, Geert Uytterhoeven [off-list ref] wrote:

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On Wed, Oct 22, 2014 at 5:01 PM, Ulf Hansson [off-list ref] wrote:

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+void keystone_pm_domain_attach_dev(struct device *dev)
   {
+    struct clk *clk;
       int ret;
+    int i = 0;

       dev_dbg(dev, "%s\n", __func__);

-    ret = pm_generic_runtime_suspend(dev);
-    if (ret)
-        return ret;
-
-    ret = pm_clk_suspend(dev);
+    ret = pm_clk_create(dev);
       if (ret) {
-        pm_generic_runtime_resume(dev);
-        return ret;
+        dev_err(dev, "pm_clk_create failed %d\n", ret);
+        return;
+    };
+
+    while ((clk = of_clk_get(dev->of_node, i++)) && !IS_ERR(clk)) {
+        ret = pm_clk_add_clk(dev, clk);
+        if (ret) {
+            dev_err(dev, "pm_clk_add_clk failed %d\n", ret);
+            goto clk_err;
+        };
       }

-    return 0;
+    if (!IS_ENABLED(CONFIG_PM_RUNTIME)) {

Can we not okkup two seperate callbacks instead of above check ?
I don't like this CONFIG check here. Its slightly better version of
ifdef in middle of the code.

I've found more-less similar comment on patch
"Re: [PATCH v3 1/3] power-domain: add power domain drivers for Rockchip platform"
https://lkml.org/lkml/2014/10/17/257

So, Would you like me to create patch which will enable clocks in pm_clk_add/_clk()
in case !IS_ENABLED(CONFIG_PM_RUNTIME)

I am wondering whether we actually should/could do this, no matter of
CONFIG_PM_RUNTIME.

Typically, for configurations that uses CONFIG_PM_RUNTIME, the PM
clocks through pm_clk_suspend(), will be gated once the device becomes
runtime PM suspended. Right?

Doing it unconditionally means we'll have lots of unneeded clocks running
for a short while.

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As long as the pm_clk_add() is being invoked from the ->attach_dev()
callback, we are in the probe path. Certainly we would like to have
clocks enabled while probing, don't you think?

If we wouldn't enable the clocks for CONFIG_PM_RUNTIME, when will
those be enabled?

They will be enabled when the driver does

         pm_runtime_enable(dev);
         pm_runtime_get_sync(dev);

in its .probe() method.

No! This doesn't work for drivers which have used
pm_runtime_set_active() prior pm_runtime_enable().

Sorry, but some misunderstanding is here:
1) If some code call pm_runtime_set_active() it has to ensure
that all PM resources switched to ON state. All! So, it will
be ok to call enable & get after that - these functions will only
adjust counters.

Correct.

This is also the key problem with your approach. You requires a
pm_runtime_get_sync() to trigger the runtime PM resume callbacks to be
invoked. That's a fragile design.

Why is this fragile design? Having pm_runtime_get_sync() result in
resuming the device (and in turn the PM domain it is in) if device is
suspended is the proper behavior, no?

Thanks.

-- 
Dmitry