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    SubjectRe: [PATCH V3] led: Backlight trigger for led subsystem
    On Tue 2008-10-07 17:20:32, Rodolfo Giometti wrote:
    > On Tue, Oct 07, 2008 at 03:54:20PM +0200, Pavel Machek wrote:
    > > Hi!
    > >
    > > > This patch set adds a new led trigger which emulates the backlight
    > > > behaviour: the leds are turned off and on each time the display blanks
    > > > and unblacks.
    > > >
    > > > Since backlights are usually implemented with leds this patch set is
    > > > useful for those drivers whose manage leds controller used as
    > > > backlight controller.
    > > >
    > > > The driver simply registers itself into the led subsystem and then the
    > > > user may get backlight emulation by setting the "backlight"
    > > > trigger. Moreover a driver, which usually manages more than one led,
    > > > can use some leds as "led" and the others as "backlights" at user
    > > > request.
    > >
    > > We already have backlight subsystem, it can also handle display
    > > brightness. Why not use that?
    >
    > Just to use a led as "led" or as "backlight" at user request. You can
    > do it by using:
    >
    > echo none > /sys/class/leds/lcd/trigger
    > echo backlight > /sys/class/leds/lcd/trigger
    >
    > and the led will work accordingly.
    >
    > Also a led used as "backlight" is just a normal led (you can set the
    > brightness as a normal led) but it switchs off automatically when the
    > LCD blanks.

    Ok, what is it good for? So I have backlight, charging led and hdd led
    on my zaurus. Now I can set charging led to indicate backlight... but
    why is it useful?
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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