Messages in this thread | | | Date | Thu, 25 Feb 2016 10:06:36 +0100 | From | Pavel Machek <> | Subject | Re: custom ioctl-based interface to control LED in networking (was Re: [PATCHv2 09/10] rfkill: Userspace control for airplane mode) |
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On Wed 2016-02-24 14:31:33, Johannes Berg wrote: > On Wed, 2016-02-24 at 13:14 +0100, Pavel Machek wrote: > > > > Why would it need to? It could look at default triggers for the led > > if it really wanted to. > > And then it needs to change them; if anything goes wrong error recovery > is practically impossible since the trigger information is lost > forever.
Well, conventional way to solve this is to simply name the led "acer::airplane"... that way it is persistent. We already do that for display/keyboard backlights.
> It's not my position to decide which combinations some system > integrator or userspace developer might find useful. > > Even when we add parameters to a trigger (I don't see a generic way to > do that, but please do enlighten me), you're now ignoring the issue of > the userspace controlled GSM modem...
Take a look at the blinking triggers.
> > > Really what you have here is a concept of "airplane mode", and that > > > concept is specific to the rfkill subsystem. This happens to affect > > > mostly an LED trigger, today, but as a concept it's something that > > > *should* be managed within the rfkill subsystem. > > > > How is that concept used outside the LEDs? What semantics does > > "airplane mode" have? You tried to explain "airplane mode" is not > > well defined up in this thread... > > I'd say it's well-defined for any given set of system software, so if > e.g. NetworkManager decides to define it one way, and connman another > way, there's a definition but the kernel need not interfere with it.
So... the LED changes meaning during boot? That's surely not a nice solution.
So... you rather store bit in a kernel with unclear semantics, explaining "oh I need to leave the flexibility to userland"? Sorry, that's just ugly.
> > I'm not saying that. I'm saying that LED maintainers should be Cced, > > to keep the interfaces consistent. > > I pretty much have to read it that way, since the LED API is in no way > impacted by these changes. Here's a new trigger, with some magic inner > working. No impact on the LED API.
New LED trigger and new ioctl for LED control... not matching how LEDs are normally controlled.
Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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