Re: [PATCH] sh: hibernation support - Jean-Christophe PLAGNIOL-VILLARD

From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
To: linux-sh@vger.kernel.org
Subject: Re: [PATCH] sh: hibernation support
Date: Fri, 06 Mar 2009 17:29:51 +0000	[thread overview]
Message-ID: <20090306172951.GA14883@game.jcrosoft.org> (raw)
In-Reply-To: <20090306064156.27281.35572.sendpatchset@rx1.opensource.se>

On 11:05 Fri 06 Mar     , Francesco VIRLINZI wrote:
> Hi Magnus
>>
>> Great! You should try in on some ST hardware as well. =)
>>   
> Yes I could try if it works also if we already had the hibernation on  
> memory on sh4.
>>   
>>> Is it also for sh4 with PMB? If so how are you managing the PMB?
>>> Moreover what about interrupt controller? This means after a resume from
>>> hibernation
>>> you could have a resumed device (and driver) but the interrupt controller
>>> has the right irq-line not initialized.
>>>     
>>
>> I have not tested with PMB.
> On PMB: some entries may be is already OK (the entries the bootloader  
> prepared fot linux)
> but Linux has to force an hw-initialization of the other entries
the memory init will be done by u-boot so PMB will not be a problem
the other device could be init by u-boot with a different stat than the kernel
expect, so each device will have to check its state and re-init in the good
state
>>  You are right about the interrupt
>> controller, but it works because swsusp resume boots up the system as
>> usual with an identical kernel. Look at the attached file for the
>> swsusp code flow...
>>   
> You are right until you don't use module.
> If you use a "mini-kernel" with several modules... when you will resume  
> from hibernation at the begin
> you boots again the 'mini-kernel'... after that you restore the previous 
> image and the irq line required by
> module more probably remains as it was (not-initialized).
the module will have to handle this itsself
because the kernel can not known the specicifity of each device init sequence

Best Regards,
J.