[PATCH 1/2] drivers: amba: properly handle devices with power domains

Marek Szyprowski m.szyprowski at samsung.com
Thu Nov 26 04:33:35 PST 2015


On 2015-11-26 11:59, Russell King - ARM Linux wrote:
> On Thu, Nov 26, 2015 at 11:24:50AM +0100, Ulf Hansson wrote:
>> On 26 November 2015 at 09:39, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
>>> Hello,
>>> On 2015-11-25 19:09, Russell King - ARM Linux wrote:
>>>> On Wed, Nov 25, 2015 at 02:56:10PM +0100, Ulf Hansson wrote:
>>>>> On 25 November 2015 at 14:34, Marek Szyprowski <m.szyprowski at samsung.com>
>>>>> wrote:
>>>>>> Is ignoring dev_pm_domain_attach() return value a solution for you?
>>>>> That's probably better than nothing, but I wonder if it in practice
>>>>> will have any effect?
>>>> If the PM domain is down, then trying to tread the ID is likely to oops
>>>> the kernel.
>>> In my case kernel simply hangs (no single message, even when earlyprintk is
>>> enabled)
>>> instead of oopsing, that's why I've submitted this patch.
>> Okay.
>> I suggest we go ahead and try that approach (ignoring the return
>> value). It's "quick fix", but the easiest way forward to solve the
>> problem.
>> My only concern is if such change impacts the boot time. We should do
>> some tests to see if the change is negligible, if not we should
>> probably think of something else (like keeping the PM domain powered
>> until late_init).
>> Russell, what do you think?
> I thought someone had a patch to read the ID during the match callback?

Okay, I've reused that patch and it seems to solve mthisproblem. I will 
send v2
in a few minutes.

Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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