At the weekend I responded to a message on lfs-support about
cdroms, eject, etc and it became clear that I had at least one issue
on a mostly LFS-7.4-rc system [ but with eudev instead of Bruce's
systemd-udev ] : /dev/sr0 was owned by root:root, so eject didn't
work for a user. I've now sorted it, but the implications are more
likely to impact people in BLFS than LFS so I'll detail it here.
I used to have a rule in /etc/udev/rules.d to create cdrom and
dvd symlinks with mode 0660 and owned by the cdrom group. That has
been part of my build for some time, I forget when and why I
originally added it. Worked fine with my previous builds in late
April.
Removing that rule from the 7.4 builds solves the ownership problem
(i.e. it becomes root:cdrom) and leaves a /dev/cdrom symlink. But
it doesn't create a /dev/dvd symlink.
I have three visual media players : xine, parole, and vlc. For
xine I'm fairly sure that it doesn't use /dev/sr0. For parole I've
no idea. I see that vlc now has an option to choose /dev/sr0
instead of /dev/dvd. But unfortunately, vlc has never worked well
for me when playing an encrypted DVD - it plays for a few seconds,
pauses, then plays a little more - so it won't be my primary means
of playing DVDs.
Long story short - upstream systemd removed the cdrw, dvd, dvdrw
symlinks after someone complained that they didn't work. If I've
understood the references (didn't see the actual discussion), with
multiple CD/DVD devices the order of appearance is random and the
links might get assigned to inappropriate devices (e.g. a dvdrw link
on a cdrom).
Fortunately, I found a post from someone at Suse regretting this
decision, and a reference to mageia applying a rule change from
openSUSE. Now that I know where the openSUSE srpms can be found, I
downloaded their systemd-206-3.1.src.rpm. Within that is a patch
which creates cdrw, dvd, dvdrw symlinks for /dev/sr0. I've attached
it in case it is useful to anyone (apply it before installing "udev"
or "gudev").
I only want a /dev/dvd symlink for /dev/sr0 and that can be created
with a sed (a long line is added, your mail client might reformat it)
sed -i '/SYMLINK.*cdrom/ a\
KERNEL=="sr0", ENV{ID_CDROM_DVD}=="1", SYMLINK+="dvd",
OPTIONS+="link_priority=-100"' \
/lib/udev/rules.d/60-cdrom_id.rules
AFAICS either fix ought to work on the LFS udev-systemd
combination.
ĸen, still kidding myself I'll get to bed at a sensible time one of
these nights :)
--
das eine Mal als Tragödie, dieses Mal als Farce
From: Robert Milasan <[email protected]>
Date: Tue, 12 Feb 2013 09:16:23 +0000
Subject: create default links for primary cd_dvd drive
cdrom_id: created links for the default cd/dvd drive (bnc#783054).
---
rules/60-cdrom_id.rules | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- systemd-206.orig/rules/60-cdrom_id.rules
+++ systemd-206/rules/60-cdrom_id.rules
@@ -15,6 +15,9 @@ ENV{DISK_EJECT_REQUEST}=="?*", RUN+="cdr
# enable the receiving of media eject button events
IMPORT{program}="cdrom_id --lock-media $devnode"
-KERNEL=="sr0", SYMLINK+="cdrom", OPTIONS+="link_priority=-100"
+KERNEL=="sr0", ENV{ID_CDROM}=="1", SYMLINK+="cdrom",
OPTIONS+="link_priority=-100"
+KERNEL=="sr0", ENV{ID_CDROM_CD_RW}=="1", SYMLINK+="cdrw",
OPTIONS+="link_priority=-100"
+KERNEL=="sr0", ENV{ID_CDROM_DVD}=="1", SYMLINK+="dvd",
OPTIONS+="link_priority=-100"
+KERNEL=="sr0", ENV{ID_CDROM_DVD_RW}=="1", SYMLINK+="dvdrw",
OPTIONS+="link_priority=-100"
LABEL="cdrom_end"
--
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