Re: [PATCH v3 0/2] clk: improve handling of orphan clocks

Tero Kristo
2015-05-07T08:23:08Z

On 05/02/2015 02:40 AM, Stephen Boyd wrote:
> On 05/01/15 15:07, Heiko Stübner wrote:
>> Am Freitag, 1. Mai 2015, 13:52:47 schrieb Stephen Boyd:
>>
>>>> Instead I guess we could hook it less deep into clk_get_sys, like in the
>>>> following patch?
>>> It looks like it will work at least, but still I'd prefer to keep the
>>> orphan check contained to clk.c. How about this compile tested only patch?
>> I gave this a spin on my rk3288-firefly board. It still boots, the clock tree
>> looks the same and it also still defers nicely in the scenario I needed it
>> for. The implementation also looks nice - and of course much more compact than
>> my check in two places :-) . I don't know if you want to put this as follow-up
>> on top or fold it into the original orphan-check, so in any case
>>
>> Tested-by: Heiko Stuebner <heiko@sntech.de>
>> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
>
> Thanks. I'm leaning towards tossing your patch 2/2 and replacing it with
> my patch and a note that it's based on an earlier patch from you.

FWIW, just gave a try for these two patches on all TI boards I have
access to.

Tested-by: Tero Kristo <t-kristo@ti.com>

I didn't try your evolved patch though, as you don't seem to have made
your mind yet.

-Tero

>
>>
>>
>>> This also brings up an existing problem with clk_unregister() where
>>> orphaned clocks are sitting out there useable by drivers when their
>>> parent is unregistered. That code could use some work to atomically
>>> switch all the orphaned clocks over to use the nodrv_ops.
>> Not sure I understand this correctly yet, but when these children get
>> orphaned, switched to the clk_nodrv_ops, they won't get their original ops
>> back if the parent reappears.
>>
>> So I guess we would need to store the original ops in secondary property of
>> struct clk_core and I guess simply bind the ops-switch to the orphan state
>> update?
>
> Yep. We'll need to store away the original ops in case we need to put
> them back. Don't feel obligated to fix this either. It would certainly
> be nice if someone tried to fix this case at some point, but it's not
> like things are any worse off right now.
>