Re: [linux-pm] [RFC] ACPI vs device ordering on resume

[Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>]

Stephen Hemminger wrote:
> On Fri, 01 Dec 2006 20:45:51 +0300
> Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com> wrote:
>
>   
>> Linus Torvalds wrote:
>>     
>>> On Fri, 1 Dec 2006, Pavel Machek wrote:
>>>
>>>   
>>>       
>>>>>> So it looks like we need this sequence:
>>>>>>
>>>>>> enable_nonboot_cpus() /* INIT */
>>>>>> finish()	/* _WAK */
>>>>>> device_resume()
>>>>>>         
>>>>>>             
>>>>> Can somebody remind me about this immediately after 2.6.19?
>>>>>       
>>>>>           
>>>> Remind. But note that freezer is not yet SMP safe... Rafael is working
>>>> on that.
>>>>     
>>>>         
>>> Thanks.
>>>
>>> On the other hand, I really wonder (and suspect) whether the problem isn't 
>>> really the freezer or even the kernel resume ordering, but simply an ACPI 
>>> internal resume ordering thing.
>>>
>>> Doesn't ACPI have per-device "WAK" calls anyway? Shouldn't we just call 
>>> those _individually_ as we walk the device tree (perhaps in the 
>>> "early_resume" stage) rather than calling them all in one chunk?
>>>
>>> 		Linus
>>>   
>>>       
>> _WAK method is system-wide. Individual objects do not have their own 
>> resume methods.
>> One way of reordering internal ACPI resume is done in patch series to 
>> 7122, I mentioned that earlier.
>> It's possible to resume ACPI devices after execution of _WAK in pm->finish.
>>     
>
> Does it solve the original problem where finish() was getting run after
> device_resume(), and finish() was corrupting PCI register settings like
> MSI?
>
>   
No, only the case with ACPI devices... all other devices are untouched.