Impacts of disabling Automatic Power Management
pgf at laptop.org
Wed Feb 8 22:38:43 EST 2012
> On 5 February 2012 10:12, Sridhar Dhanapalan <sridhar at laptop.org.au> wrote:
> > On 5 February 2012 02:35, Martin Langhoff <martin.langhoff at gmail.com> wrote:
> >> On Sat, Feb 4, 2012 at 10:26 AM, Samuel Greenfeld <greenfeld at laptop.org>
> >>> Disabling suspend during collaboration was discussed a year ago, but as far
> >>> as I know this has not made it into any 11.3.x build:
> >>> http://dev.laptop.org/ticket/10363
> >> Thanks for that! I had forgotten ~
> >> Sridhar, Jerry -- that bug has a patch that implements exactly the
> >> Sugar change I was proposing.
> >> We later dropped it for a change to powerd that we thought would cover
> >> all the bases by relying on using wake-on-LAN on the wlan... which we
> >> later learned is somewhat buggy.
> >> Please test with this patch and let us know whether it helps.
> > Thanks! We'll add this to our next dev build.
> In our next build, we will be doing two things :
> 1. enabling the patch
> 2. disabling wake-on-LAN
> It seems to me that this is the preferred solution. I think we only
> need to inhibit power management when collaboration is active, not for
> any LAN traffic.
> Living up to its name, wake-on-LAN keeps the XOs awake whenever a
> network connection is active, even when you don't really need it to
> be. Assuming that it always works as intended (which as you have
> explained, it does not), the patch won't be very testable when it is
i guess you're saying that an active network connection should be
keeping the laptop awake, and therefore being able to wake it up after
it sleeps is a moot point. that may be true for chatty collaboration
protocols -- it certainly wouldn't be true for TCP sessions (which isn't
your use case -- i understand that).
but in addition, without wake-on-lan, a sleeping laptop will be
invisible to its peers, at least until the user wakes it up. is that
> erikos reckons that the patch won't do much , but the testing
> performed so far seems to be small-scale. Hopefully we'll get some
> feedback on this after we put out our build.
>  https://dev.laptop.org.au/issues/1049
>  http://dev.laptop.org/ticket/10363#comment:21
> Sridhar Dhanapalan
> Engineering Manager
> One Laptop per Child Australia
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paul fox, pgf at laptop.org
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