Re: [PATCH][RFC][ModemManager] udev rules: port to hwdb where applicable

[Kay Sievers <kay vrfy org>]

On Tue, Jul 23, 2013 at 12:46 PM, Tom Gundersen <teg jklm no> wrote:
> On 22 Jul 2013 17:43, "Dan Williams" <dcbw redhat com> wrote:
> > On Sat, 2013-07-20 at 01:53 +0200, Tom Gundersen wrote:
> > > Udev recently gained a hardware database, which is an efficent
> > > replacement for
> > > the kind of rules shipped with modemmanager.
> > >
> > > This patch ports all the relevant udev rules to hwdb format, which
> > > should
> > > significantly speed up the processing of usb add events.
> >
> > Which is nice, but it's significantly less clear and readable than the
> > udev rules, unfortunately.  Is there any way we can autogenerate the
> > hwdb stuff from the udev rules and just install that instead, but keep
> > editing the udev rules?
>
> I don't think it would be impossible, but at the same time I don't see how
> to do it in a reasonable and robust way. I'm cc'ing Kay in case he wants to
> prove me wrong.
>
> Another option would be to introduce a new, special purpose, intermediate
> language, see e.g. how media-player-info does it.
>
> However, are you sure it is worth the effort? We only have four different
> (and largely overlapping) patterns in use, so if we add the right
> documentation/comments at the top of all the rules files it should be easy
> enough to edit, don't you think?

The modalias string is not the prettiest thing yeah, but it's how the
kernel modules and all the rest works now. I guess it's just a matter
of getting used to.

Projects could maintain the data in any format that fits their need,
sure, and export udev rule or hwdb files. It makes fixes and additions
from users more complicated though, because they will probably send it
in the hwdb format.

There is currently no plan to ship a converter in upstream systemd
though to convert udev rules to hwdb.

Kay