Subject: Re: [PATCH] Enable backlight when trigger is activated

From: Pavel Machek <[email-masked]>
Date: Mon, 22 Jul 2019 09:50:32 +0200

Hi!

> > Configuring backlight trigger from dts results in backlight off during
> > boot. Machine looks dead upon boot, which is not good.
> > 
> > Fix that by enabling LED on trigger activation.

> > +++ b/drivers/leds/trigger/ledtrig-backlight.c
> > @@ -114,6 +114,8 @@ static int bl_trig_activate(struct led_classdev *led)
> >  	n->old_status = UNBLANK;
> >  	n->notifier.notifier_call = fb_notifier_callback;
> >  
> > +	led_set_brightness(led, LED_ON);
> > +
> 
> This looks fishy.
> 
> Maybe you should use a default-state = "keep" instead? (and you'll have
> to support it in the LED driver).
> 
> That'll give you proper "don't touch the LED if it was turned on" behavior,
> which is what you seem to want.

Actually no, that's not what I want. LED should go on if the display
is active, as soon as trigger is activated.

Unfortunately, I have see no good way to tell if the display is
active (and display is usually active when trigger is activated).

Thanks,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel