Re: [PATCH v5 2/6] leds: triggers: Add a keyboard backlight trigger

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On Thursday 24 November 2016 16:32:06 Jacek Anaszewski wrote:
> Since it has been reported that POLLPRI notifications on brightness
> file can lead to increased power consumption, and having my above
> statement I don't think that it is a good idea to use brightness
> file for this.

How is brightness file different from others that it cannot issue
POLLPRI notification?

I understood that problem is there in case that LED level is changed too
many times per second (like by CPU trigger).

If this is not that problem can you describe real issue, why we cannot
use POLLPRI for brightness file?

> >Yes, how triggers interact with brightness file, what happen when you
> >write 0 on active trigger,
> 
> There is already a patch in linux-next adding the following:
> 
> 
> +		Writing 0 to this file clears active trigger.
> +
> +		Writing non-zero to this file while trigger is active changes the
> +		top brightness trigger is going to use.
> +

Great!

> >what happen when you read brightness file
> >with active trigger / without trigger.
> >
> 
> Yes, this needs to be covered too.

-- 
Pali Rohár
pali.rohar@xxxxxxxxx
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