Update on DeviceKit

[Matthew Garrett]

On Wed, May 07, 2008 at 05:03:30PM +0200, Lennart Poettering wrote:

> I think it would be best if backlight control is left to X. For some
> graphics cards its already properly exported in XRANDR. XRANDR knows
> about multiple screens, hotplug and stuff, is network transparent and
> so on. It's also much easier for normal desktop apps like cheese to
> use the backlight as a flash if its exported via XRANDR.

I'm not entirely sold on this - it does mean that we're then tied to a 
fairly X-centric model. What's the issue with cheese (and similar) 
applications using a dbus call for this purpose?

> For those devices where backlight control cannot be done via the
> graphics hardware the kernel interfaces should be hooked up to X. And
> there are already many cases were brightness can be controlled via the
> gfx hw (i.e. X) but not via the kernel interfaces.

Unfortunately, in many cases X is going to have to fall back to driving 
the kernel interface - a great deal of hardware assumes that the 
firmware is the only thing driving the brightness controls. As we move 
to more intelligent kernel support for graphics hardware, it's likely 
that everything will be exposed via the kernel interface in any case.

> (Oh, and I'd love to see someone taking
> http://ddccontrol.sourceforge.net/ and making a module for X of it, so
> that we could control the backlight of external LCD screens via XRANDR
> too ;-))

Adam Jackson has done some work on this, but I don't know how far he 
got.
-- 
Matthew Garrett | mjg59 at srcf.ucam.org