[PATCH 1/3] clk: exynos-audss: Keep the parent of mout_audss always enabled

Doug Anderson dianders at google.com
Tue Jun 24 21:02:33 PDT 2014


On Tue, Jun 24, 2014 at 8:09 PM, Tushar Behera <trblinux at gmail.com> wrote:
> On 06/25/2014 04:29 AM, Doug Anderson wrote:
>> Tushar,
>> On Thu, Jun 12, 2014 at 12:40 AM, Tushar Behera <tushar.b at samsung.com> wrote:
>>> On Wed, Jun 11, 2014 at 10:20 PM, Kevin Hilman <khilman at linaro.org> wrote:
>>>> Tushar Behera <tushar.b at samsung.com> writes:
>>>>> When the output clock of AUDSS mux is disabled, we are getting kernel
>>>>> oops while doing a clk_get() on other clocks provided by AUDSS.
>>>>> Though user manual doesn't specify this dependency, we came across
>>>>> this issue while disabling the parent of AUDSS mux clocks.
>>>>> Keeping the parents of AUDSS mux always enabled fixes this issue.
>>>> While this patch works (and fixes the boot problem for me), it seems
>>>> like it's papering over the real problem.
>>> Thanks for testing.
>>>> Seems like the right fix is actually modelling the clocks properly so
>>>> that enabling a child clock ensures that the parent is also enabled.
>>> Patch 2/3 was to ensure we have proper clock tree defined for
>>> Exynos5420. While testing with audio disabled, that patch alone fixed
>>> the issue. But when audio was enabled (and hence I2S0 was trying to
>>> access the clocks), we got some kernel oops during late booting, hence
>>> I came up this solution.
>>> The solution might be a little half-baked because of the urgency to
>>> push the fix, but will try to dig more into the issue on Monday when I
>>> resume office.
>> Which Monday were you referring to?  ;)
> Sorry that I couldn't get deeper into this issue. Thanks for reminding
> though.

No problem.  I know how it is.  I was trying to be funny though
sometimes that doesn't come through very well over email.

>> ...but in all seriousness do you have an official status update on
>> this patch?  It seems as if it's not needed and all you need is
>> <https://patchwork.kernel.org/patch/4333581/>, but it would be nice to
>> get an official confirmation.
> I have tested various scenarios with only patch 2/3, which seems to be
> sufficient for the time being. I have not encountered the older issue
> till now. I was thinking of testing a bit further, but given that you
> have already asked for, we can go ahead with only patch 2/3 right now.
> In case any further issue comes up, I will post patch 1/3 as per the
> review comments that I have got.

Sounds like a plan.  Thanks for getting the original patch sent out so
quickly after I reported it.

Hopefully Kukjin will apply pack 2/3 soon (today?)

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