Re: [PATCH 02/24] leds: core: Add support for composing LED class device names

From: Pavel Machek
Date: Mon Nov 12 2018 - 05:35:19 EST


Hi!

> >> It's overcomplicating the naming again. In every case you can tweak
> >> the function name to eth0_link, eth1_link etc.
> >
> > Well, but in such case it would be good to keep existing scheme.
> >
> > My system looks like this:
> >
> > input16::capslock tpacpi::bay_active tpacpi::standby
> > input16::numlock tpacpi::dock_active tpacpi::thinklight
> > input16::scrolllock tpacpi::dock_batt tpacpi::thinkvantage
> > input5::capslock tpacpi::dock_status1 tpacpi::unknown_led
> > input5::numlock tpacpi::dock_status2 tpacpi::unknown_led2
> > input5::scrolllock tpacpi:green:batt tpacpi::unknown_led3
> >
> > I agree that we should get rid of "tpacpi:" part in some cases. But
> > it does not make sense to get rid of "input16:" part -- it tells you
> > if the LED is on USB or on built-in keyboard.
> >
> > Ideally, tpacpi::thinklight would be input5::frontlight (as it is
> > frontlight for the keyboard).
> >
> > Yes we should simplify, but it still needs to work in all cases.
>
> Well, label is not being removed. You still can use it an the old
> fashion, even when using new led_compose_name().
>
> Maybe removing the description of the old LED naming from
> Documentation/leds/leds-class.txt was too drastic move.
> I'll keep it next to the new one, and only add a note that
> it is kept only for backwards compatibility.

I agree that removing it is "just too drastic".

But it is not just for backwards compatibility. See my examples above,
it is needed to tell which device the LED is asociated with, and it is
absolutely required for USB devices (for example).

And even for "embedded" stuff like routers, we want eth0:green:link,
eth0:yellow:activity and not some kind of hack.

Ideally, colors would come from fixed list, functions would come from
fixed list, and device part would come from name used elsewhere in the
kernel.

(And yes, it probably means we should have something in device tree to
link LED to its device. device = "name" would be good start...)

Pavel

--
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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