[systemd-devel] When and why was write_cd_rules and 75-cd-aliases-generator.rules where dropped?

Kay Sievers kay at vrfy.org
Thu Feb 7 05:11:13 PST 2013

On Thu, Feb 7, 2013 at 1:46 PM, Robert Milasan <rmilasan at suse.com> wrote:
>  just notice that in newer version of systemd-udev (195) write_cd_rules
>  and 75-cd-aliases-generator.rules have been dropped. Can anybody give
>  me the commit for that (tried to find it, but didn't)?

None of the "rule generator stuff" was ported to systemd. This
facility created far more problems than it ever solved. Many people
ended up with unsolvable problems, network interfaces names like
rename3, or with rules files with 1000s of dead entries. It did not
work properly for virtualization, and and and ...

We just need admit today that it was a big mistake to ever try to
write system config from hotplug handlers. We should have dropped that
misguided thing much earlier.

In short: we tried to be smart, but it turned out, we are not smart
enough to fulfill the promise. So we finally killed it, and it will
not come back.

> Also shouldn't we add a
> default /dev/dvd, /dev/cdrom, /dev/cdrw, /dev/dvdrw for the primary
> cd/dvd drive?
> I'm asking this because apps like VLC are trying always to
> read /dev/dvd to play DVD and in some cases some users don't know
> that /dev/sr0 or /dev/cdrom is that same thing.

Because these links make the most sense when we support multiple
drives, and as mentioned above, we don't want to support any kind of
stateful rules anymore. We just do the absolute minimum today, and
that is /dev/cdrom.

People actually asked to remove /dev/dvd link we created in the
initial code, to not make any promises anymore, and not make it look
like multiple devices are supported:

Your rules look fine, but we don't want to add them upstream, we just
provide the absolute minimum these days, and people should fix their
apps to query for devices, or add custom (or the distribution does)
rules to support legacy requirements.


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