backlight device, suspend/resume...
Sean McNeil
sean at mcneil.com
Wed Jul 9 01:11:28 CEST 2008
This is an area I have a strong opinion about...
Chris Ball wrote:
> Hi,
>
> > Mike (mwester) wrote:
> >> In practice, compromise is necessary. Can we at least let the
> >> kernel bring the backlight up to a level that would allow the user
> >> to see vague outlines of something on the screen? Or failing
> >> that, can we make the backlight level on resume configurable in
> >> some way?
>
> > If you need this, why not set the backlight to "dim" instead of
> > "off" before requesting the suspend ?
>
> > The secret about successful kernel programming is to do as little
> > as possible in the kernel :-)
>
> At OLPC, we're using a small userspace policy daemon called OHM¹ to make
> decisions like these -- when to dim, when to suspend, how to tell if the
> user is "idle". I'd be happy to help get it running on the FR if it's
> wanted.
>
IMHO, OLPC is doing the right thing here as an application. The kernel
provides functionality and does things at a very low level. You do not
want it to be providing any utilitarian functionality. I would disagree
that there is compromise necessary. Sure, one can have debug code that
turns on the display coming out of sleep, but a release should do the
right thing and leave the display in exactly the same condition it was
in when it entered suspend.
This is the same reasoning I don't want any of the LEDs to be doing
utilitarian things like being changed when external power is
applied/removed - the kernel is not an application. I would be surprised
if application capabilities such as these manage to make it upstream
into the main kernel tree.
Cheers,
Sean
More information about the openmoko-kernel
mailing list