[PATCH] intel_display.c: make acpi_video last in backlight_interfaces

Alon Levy alevy at redhat.com
Sun Aug 26 07:52:44 PDT 2012

On Sun, Aug 26, 2012 at 03:45:15PM +0100, Chris Wilson wrote:
> On Sun, 26 Aug 2012 16:31:41 +0200, Alon Levy <alevy at redhat.com> wrote:
> > OK. I'm not sure what would be better for gnome / your-favorite desktop
> > manager. One option is to write an xorg.conf file with this patch.
> > Another is a property for the backlight interface. Even though it's
> > abuse of the property interface for a one time thing (not like it would
> > change during the lifetime of X). Right now it's a stopgap thing, but
> > not very user friendly. This patch came from my brother complaining that
> > with his mac he can lower the backlight all the way to 0, but not with
> > his linux laptop. I don't want to have to maintain an xorg.conf file.
> > 
> > Sorry for the blurb - bottom line, I'm not sure if an xorg.conf file
> > would be something management, i.e. libgnome-desktop / kde etc. would
> > want to deal with, setting a property is perhaps easier, or another
> > solution.
> I would argue that the manufacturer expected the OS to use DPMS to turn
> the backlight completely off and save further power when opting to have
> it minimal backlight setting at non-zero.

That sounds right, thanks! Now it just becomes something that the
application (in my case libgnomedesktop) has to deal with, i.e. if
laptop brand X use DPMS for 0 brightness, else not. Or maybe always
using it would also work. I guess this patch is not required in this
case, better drop it unless you know, you like it :)

> Maybe that is the better answer, have gnome-power-manager turn off the
> display when setting the backlight to 0. Given that we have separate
> X properties for backlight and DPMS, I would prefer to leave that
> decision up to the application / user.
> -Chris
> -- 
> Chris Wilson, Intel Open Source Technology Centre

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