Re: A desktop environment[1] kernel wishlist

[Bastien Nocera <hadess@hadess.net>]

On Thu, 2014-10-30 at 11:05 -0400, Theodore Ts'o wrote:
> On Thu, Oct 30, 2014 at 03:45:02PM +0100, Bastien Nocera wrote:
> > > Actually Maemo people (on Nokia N900 and friends) got it right: unlike
> > > android devices, it does not suspend to RAM at any point, and still
> > > has reasonable battery life.
> > 
> > Android devices don't suspend to RAM. Neither do Tizen devices AFAIK.
> 
> Actually, Android devices have historically always suspended the CPU
> whenever there wasn't a wakelock keeping the device to suspend.  You
> might not consider this "suspend to RAM" but in fact it uses the
> identical kernel and hardware facilities as the legacy "suspend to
> RAM" mechanism.

I wouldn't consider this "suspend to RAM", but that's because I expect
the firmware to implement most of that. Anyway, that's splitting hair.

> > I don't think anyone was discussing cell phones in particular in this
> > thread, and knowing when user-space got woken up because of the baseband
> > processor having information for us would still be useful.
> 
> It matters because for laptops, what's important is whether the lid is
> closed or not.  Whether and how the laptop was "woken" is really
> beside the point, as others have argued.  Your counter argument is
> that tablets don't have lids.  But tablets are going to be using
> schemes similar to Android, Tizen, and Maemo, and they are *not* going
> to be using the legacy suspend-to-RAM model, because it's not
> sufficiently good at power saving.

There are plenty of tablets around that aren't Android devices. There
are plenty of laptops that can be switched to a tablet mode for which
this wouldn't apply either.