Re: [PATCH V5 0/7] cpufreq: suspend early/resume late: dpm_{suspend|resume}()

From: Linaro
Date: Wed Feb 19 2014 - 20:49:53 EST




> On 19-Feb-2014, at 10:56 pm, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote:
>
>> On 02/18/2014 09:15 PM, Viresh Kumar wrote:
>>> On 19-Feb-2014 1:48 AM, "Stephen Warren" <swarren@xxxxxxxxxxxxx> wrote:
>>>
>>>> On 02/17/2014 02:20 AM, Viresh Kumar wrote:
>>>>> On 15 February 2014 05:33, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote:
>>>>> On 02/14/2014 03:23 PM, Rafael J. Wysocki wrote:
>>>>
>>>>>> Well, it would be good to verify which part, then.
>>>>>
>>>>> Patch 2/7 appears to stop that message from being printed during
>>>>> suspend, and perhaps reduce the number of times it's printed during
>>>>> resume. Patch 7/7 stops the message being printed at all.
>>>>>
>>>>> Looking at patch 7, I wonder if it's simply because tegra_target() was
>>>>> modified never to return -EBUSY, so the bug is still there, but it's
>>>>> just been hidden.
>>>>
>>>> No, the bug is removed now. Its hidden in current linus/master :)
>>>
>>> I'm not sure what that means; I still see the message:
>>
>> I have given a better reply in one of the earlier mails in this thread.
>> And skipped a more elaborative reply now.
>>
>> So this failure was always there since long time, as you disable your
>> target() fn early in suspend. But the message wasn't printed earlier.
>>
>> A recently added core patch started printing this, so not a new bug.
>> But this series fixes suspend resume completely and you wouldn't see it
>> anymore.
>
> OK, so I suppose we have two options:
>
> a) Just ignore the kernel error spew since it's a known issue.
>
> b) If I make the Tegra driver return 0 rather than -EBUSY, would that
> work? It would certainly silence the error. However, I wonder if it
> would cause the cpufreq core to get out of sync with HW; the core would
> think that it'd set some frequency, which the driver ignored, and if it
> later wanted to switch frequency, the call might get skipped because the
> core thought the HW was already set to that frequency?

Option is the one you need.--
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