Re: [libgpiod] feature request: output state read and sustain

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Wed, Jun 29, 2022 at 12:58 PM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
>
> On Wed, Jun 29, 2022 at 12:48 PM Kent Gibson <warthog618@xxxxxxxxx> wrote:
> > On Wed, Jun 29, 2022 at 12:27:13PM +0200, Andy Shevchenko wrote:
> > > On Wed, Jun 29, 2022 at 11:27 AM Jiří Prchal <jiri.prchal@xxxxxxxxxxx> wrote:
>
> ...
>
> > > Do not use shell. Use proper programming language that may give you an
> > > easier way of handling this, i.e. _context_. Shell tools are
> > > _context-less_ and here is the problem you are trying to solve, but
> > > from the wrong end.
> >
> > Actually my proposed gpioset for v2 will support running interactively
> > so it can maintain context and be driven from shell - for cases where
> > basic scripting will suffice.
>
> Dunno if it's the right direction and if I missed any (additional) discussion.
> As far as I remember the idea was to introduce DBus aware daemon that
> should handle the context of the line and at the same time consider security

And it's still very much on the roadmap.

> implications. Allowing shell to be context-aware is a hidden mine
> field. What will happen if the script/user forgets to move the line to
> the proper state and the chip will drain a lot of current? So, at
> least PM concerns just popped up immediately to my mind. What else can
> be problematic? So, I dunno, it's a good idea to allow shell to leave
> a line in some state when the user actually doesn't care about it
> anymore. At the bare minimum this mustn't be default behaviour.
>

It's not much different from letting your current gpioset run in the
background, is it?

Kent just submitted his first version of gpioset, you can take a look
at it and review it. :)

Bart

> --
> With Best Regards,
> Andy Shevchenko