[ltp] Re: Generic battery interface

[Shem Multinymous]

On 7/29/06, Vojtech Pavlik <vojtech@suse.cz> wrote:
> > I think what people want from device choice is a reasonable default
> > plus a convenient way to override things. The former is handled nicely
> > by distributions' udev rules, while the latter is best done by
> > providing fixed paths. As an end-user, if I know my favorite joystick
> > is on a specific USB port (hence a specific syfs directory), then I
> > want to tell neverball "use that one" without setting up nasty udev
> > rules or playing major:minor matchup. Yes, that's bypassing the Proper
> > Udevian Way of Doing Things, but it's so much easier and Unix-like
> > that we really should make it possible (though not by default!).
>
> IMO the right way here would be to have a nice GUI for configuring udev
> included with the distro, that'd let you browse the sysfs tree and
> point'n'click to create the rule you need.

That's still an extra level of indirection. You have to use the nice
GUI to create a new /dev/something, and then point your at at dev
/dev/something. And you have to be root to do that, whereas some sysfs
stuff is world-readable.


> > Security issues aside (for a moment):
> > Is there any reason not to provide real device inodes on sysfs,
> > instead of just a textual /sys/foo/dev? And then, maybe udev should
> > symlink to those device files under /sys instead of creating its own?
> > This would tie the two systems together rather elegantly.
>
> The reason behind this was to force people NOT use sysfs directly when
> interfacing to the OS. ;)
>
> Because sysfs wasn't intended to be an API you can rely on, one that's
> fixed in stone and cannot be changed for compatibility reasons. I
> believe it failed in that respect.

Is sysfs supposed to be a private" API that only "special services
services" look at? It has definitely failed in this respect -- It's
just too convenient and attractive. I'm not sure that's a bad thing...

Given the current usage pattern of sysfs, is it still a bad idea for
it to carry device inodes?

  Shem