Documentation on /sys/power/resume

Documentation on /sys/power/resume

[Bill Davidsen]

Not in the ABI doc, is there and doc at all, and if not could someone 
who knows where it's used might give me a hint, as a quick look didn't 
bring enlightenment. Or is it a future hook which doesn't work yet?

-- 
Bill Davidsen <davidsen@tmr.com>
  "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: Documentation on /sys/power/resume

[Rafael J. Wysocki]

Hi,

On Sunday, 27 May 2007 01:51, Bill Davidsen wrote:
> Not in the ABI doc, is there and doc at all, and if not could someone 
> who knows where it's used might give me a hint, as a quick look didn't 
> bring enlightenment. Or is it a future hook which doesn't work yet?

That's something that in theory may allow you to resume the system from
and initrd script.

Basically, you write your resume device's major and minor numbers
into it as the "MAJ:MIN" string (eg. "8:3" for /dev/sda3 on my box) and the
kernel will try to read the image from this device and restore it.

It only works with partitions and the use of it us discouraged, so it's
deliberately undocumented.

Greetings,
Rafael


-- 
If you don't have the time to read,
you don't have the time or the tools to write.
		- Stephen King

Re: Documentation on /sys/power/resume

[Bill Davidsen]

Rafael J. Wysocki wrote:
> Hi,
> 
> On Sunday, 27 May 2007 01:51, Bill Davidsen wrote:
>> Not in the ABI doc, is there and doc at all, and if not could someone 
>> who knows where it's used might give me a hint, as a quick look didn't 
>> bring enlightenment. Or is it a future hook which doesn't work yet?
> 
> That's something that in theory may allow you to resume the system from
> and initrd script.
> 
> Basically, you write your resume device's major and minor numbers
> into it as the "MAJ:MIN" string (eg. "8:3" for /dev/sda3 on my box) and the
> kernel will try to read the image from this device and restore it.
> 
> It only works with partitions and the use of it us discouraged, so it's
> deliberately undocumented.
> 
Thanks, that's just different enough from what little info I had to make 
what I have not work. I'm looking at resume from a non-swap location.

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: Documentation on /sys/power/resume

[Rafael J. Wysocki]

On Sunday, 27 May 2007 14:53, Bill Davidsen wrote:
> Rafael J. Wysocki wrote:
> > Hi,
> > 
> > On Sunday, 27 May 2007 01:51, Bill Davidsen wrote:
> >> Not in the ABI doc, is there and doc at all, and if not could someone 
> >> who knows where it's used might give me a hint, as a quick look didn't 
> >> bring enlightenment. Or is it a future hook which doesn't work yet?
> > 
> > That's something that in theory may allow you to resume the system from
> > and initrd script.
> > 
> > Basically, you write your resume device's major and minor numbers
> > into it as the "MAJ:MIN" string (eg. "8:3" for /dev/sda3 on my box) and the
> > kernel will try to read the image from this device and restore it.
> > 
> > It only works with partitions and the use of it us discouraged, so it's
> > deliberately undocumented.
> > 
> Thanks, that's just different enough from what little info I had to make 
> what I have not work. I'm looking at resume from a non-swap location.

Only suspend2 can do this right now.  The built-in swsusp can resume from a
swap file as long as it's not located on LVM.

Greetings,
Rafael

Re: Documentation on /sys/power/resume

[Bill Davidsen]

Rafael J. Wysocki wrote:
> On Sunday, 27 May 2007 14:53, Bill Davidsen wrote:
>   
>> Rafael J. Wysocki wrote:
>>     
>>> Hi,
>>>
>>> On Sunday, 27 May 2007 01:51, Bill Davidsen wrote:
>>>       
>>>> Not in the ABI doc, is there and doc at all, and if not could someone 
>>>> who knows where it's used might give me a hint, as a quick look didn't 
>>>> bring enlightenment. Or is it a future hook which doesn't work yet?
>>>>         
>>> That's something that in theory may allow you to resume the system from
>>> and initrd script.
>>>
>>> Basically, you write your resume device's major and minor numbers
>>> into it as the "MAJ:MIN" string (eg. "8:3" for /dev/sda3 on my box) and the
>>> kernel will try to read the image from this device and restore it.
>>>
>>> It only works with partitions and the use of it us discouraged, so it's
>>> deliberately undocumented.
>>>
>>>       
>> Thanks, that's just different enough from what little info I had to make 
>> what I have not work. I'm looking at resume from a non-swap location.
>>     
>
> Only suspend2 can do this right now.  The built-in swsusp can resume from a
> swap file as long as it's not located on LVM.
>   
Sounds like sispend2 is still needed, I haven't needed a suspending 
kernel in a few years, and I was hoping that with suspend working in 
mainline that resume would have been implemented. Sounds as if that's 
not the case, my swap is RAID1, I was hoping to resume from one of the 
mirrors, since they are based on a partition. No joy wit or without 
/sys/power/resume, so I'll look further.

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979

Re: Documentation on /sys/power/resume

[Matthew Garrett]

On Sun, May 27, 2007 at 09:17:25AM -0400, Bill Davidsen wrote:

> Sounds like sispend2 is still needed, I haven't needed a suspending 
> kernel in a few years, and I was hoping that with suspend working in 
> mainline that resume would have been implemented. Sounds as if that's 
> not the case, my swap is RAID1, I was hoping to resume from one of the 
> mirrors, since they are based on a partition. No joy wit or without 
> /sys/power/resume, so I'll look further.

Should work absolutely fine as long as you set up the RAID before 
attempting to resume.

-- 
Matthew Garrett | mjg59@srcf.ucam.org