[PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled

Daniel Lezcano daniel.lezcano at linaro.org
Mon May 19 09:45:56 PDT 2014

On 05/16/2014 11:29 PM, Tony Lindgren wrote:
> * Santosh Shilimkar <santosh.shilimkar at ti.com> [140516 06:43]:
>> Tony,
>> On Thursday 15 May 2014 02:29 PM, Santosh Shilimkar wrote:
>>> On Thursday 15 May 2014 01:54 PM, Santosh Shilimkar wrote:
>>>> On Thursday 15 May 2014 01:50 PM, Daniel Lezcano wrote:
>>>>> On 05/15/2014 07:03 PM, Santosh Shilimkar wrote:
>>> [..]
>>>>>>> With above mentioned change, it should work. Other alternatives is OMAP4 driver does
>>>>>>> its won registration where it can start the timer. The way it was before the
>>>>>>> consolidation.
>>>>>>> Ofcourse if you have better fix, then great.
>>>>>> What is your suggestion. We *must* fix the regression asap. I think
>>>>>> $subject patch with an update to bctimer start under CPUIDLE_FLAG_COUPLED
>>>>>> seems a good way forward.
>>>>>> Do let me know.
>>>>> Did you see Alex Shi's email [cc'ed] ? Reverting this change makes the panda ES to hang.
>>>> The hang is definitely due to the bctimer not started. As I said, I assumed it was and
>>>> then you corrected saying it is under the flag.
>>>>> I am not convinced the culprit is this code you are trying to revert.
>>>> fair enough. Thats why I said if you have an alternative fix thats great.
>>> For record, below is updated patch with bctimer started which
>>> was missed in earlier version. I haven't tested it though.
>>> Alex,
>>> Please give a try with your test-case and see if you still see the hang.
>>> Am just curious about your issue and hence the request..
>> Alex tested below patch and he don't see the hang so the patch is
>> addressing the issue.
>> If Daniel works out an alternate fix to avoid reverts, that will be great
>> but if not, we should merge the below patch. I let you take call on it.
> Daniel any news on this?
> And just to recap, this problem can be reproduced with current
> Linux next with omap2plus_defconfig with CONFIG_CPU_IDLE enabled. The
> system should hang during the boot at some point.

I can take the time to investigate a bit more but not right now. What is 
your deadline before committing the reverts ?

> And for the record, the omap3 hang fix is now posted to the lists as
> "[PATCH] ARM: OMAP2+: Fix DMA hang after off-idle". This should not
> have anything to do with the omap4 cpu_idle hang as omap4 does not
> currently lose context during idle.

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