Messages in this thread | | | Date | Tue, 7 Oct 2008 20:58:46 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH V3] led: Backlight trigger for led subsystem |
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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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