[linux-pm] [RFC PATCH v4] ARM hibernation/suspend-to-disk support

[santosh.shilimkar@ti.com (Santosh Shilimkar)]

On 6/9/2011 10:37 PM, Frank Hofmann wrote:
>
>
> On Thu, 9 Jun 2011, Santosh Shilimkar wrote:
>
>> On 6/9/2011 9:56 PM, Frank Hofmann wrote:
>>>
>>>
> [ ... ]
>>> a) What reasons if any are there why cpu_{v7_do_}suspend/resume are not
>>> ok to use (on OMAP) for snapshotting core state, for the purpose of
>>> hibernation ?
>>> If there are any such issues, then how could they be addresssed ?
>>>
>> Part of the answer is what Russell described. We think it's doable,
>> but it needs some work. First and fore most is this code should
>> be able to be executed from DDR. It's not the case today.
>
> Ah, I gather that's the _real_ critical point, i.e.
>
> _omap_sram_idle = omap_sram_push(omap34xx_cpu_suspend,
> omap34xx_cpu_suspend_sz);
>
> relies on this to be completely consecutive in mem, and relocatable,
> i.e. calling _outside_ that area isn't possible ?
>
> I.e. unless a way can be found to _embed_ cpu_suspend/resume here, it's
> pretty hard to use ?
>
> Would it be possible / acceptable to have it be relocatable code, and
> put it into a common .section ?
>
Surely acceptable :)
But other points about callback are also important o.w
you will use MMU with wrong CP15 configurations after
one sleep transition.