Re: S3 is broken again in xen-unstable

[George Dunlap <george.dunlap@eu.citrix.com>]

On 04/29/2013 03:00 PM, Ben Guthro wrote:
> On Mon, Apr 29, 2013 at 7:03 AM, George Dunlap
> <George.Dunlap@eu.citrix.com> wrote:
>> On Fri, Apr 26, 2013 at 9:10 AM, Ian Campbell <Ian.Campbell@citrix.com> wrote:
>>> On Thu, 2013-04-25 at 18:02 +0100, Ben Guthro wrote:
>>>> On Thu, Apr 25, 2013 at 8:00 AM, Ben Guthro <ben@guthro.net> wrote:
>>>>> Since this is something that XenClient really relies on working, it
>>>>> has been a pain point with every upgrade of Xen for us.
>>>>> It is enormously time consuming to debug on every upgrade, and has a
>>>>> long tail in discovering problems (I started debugging S3 last Aug on
>>>>> xen-unstable, prior to 4.2 being cut)
>>>>>
>>>>> How can we work with the community to try to get some sort of
>>>>> regression testing for this feature that we rely on in our product?
>>>>
>>>> I am still interested in ideas for getting this into automated
>>>> testing, and any ideas people may have for this.
>>>
>>> CCing Ian Jackson who runs the test infrastructure.
>>>
>>> Contributing new tests is now less onerous than it once was (i.e. it
>>> might even possible at all). There is some info at
>>> http://lists.xen.org/archives/html/xen-devel/2012-10/msg01517.html
>>> although the branch may be out of date -- Ian was working on merging the
>>> standalone branch at one point.
>>>
>>> Some questions:
>>>        * How automatable is s3?
>>>        * In particular can we automate the wakeup? s3 is save to RAM
>>>          IIRC, and most power control in the test system is done with PDU
>>>          power cycling.
>>>        * Would s3 ever be expected to work on the sorts of whitebox
>>>          server systems which form the osstest pool or do we need to
>>>          investigate additional hardware?
>>>        * How hardware specific are the s3 failures -- we obviously can't
>>>          have one of every laptop ever ;-)
>>
>> When I discussed this with Ben before, it seemed that almost any
>> testing would be a very large improvement.  Namely, it seemed to me
>> that even if the test just did a "null suspend" -- i.e., shut the
>> entire system down as though about to do a suspend but then just
>> resume without pulling the trigger -- would shake out a lot of bugs
>> (as well as make it very easy for devs that don't normally care about
>> suspending their machine to fix things).  Having an RTC wake-up would
>> be the next thing to do after that.
>>
>>   -George
>
> FWIW, the patch that implements this "fake s3" functionality is
> implemented here, should it be considered for inclusion:
> http://markmail.org/message/ghj2ffngemccq6p4

[Adding xen-devel back in to the cc]

FYI playing around with this is on my to-do list, but it will probably 
be until after the 4.3 release.

  -George