Arch Linux

tehabe

Member

Registered: 2008-10-14

Posts: 82

[solved] DVD/CD Device Problems/Wrong Symlinks to the Right Place

When I put my external DVD drive on my computer the devices look like this:

/dev/dvd -> /dev/cd/dvd-4:0:0:0
/dev/cd/dvd- -> /dev/sr0

I can access the drive via /dev/sr0, /dev/cd/dvd- and even /dev/scd0 but not via /dev/dvd, because of the wrong enty in /dev/cd

This what I got from the debug messages:

Nov 17 23:27:43 proton udevd-event[3301]: '/dev/cd/cdrom-' with target '/dev/sr0' has the highest priority 0, create it
Nov 17 23:27:43 proton udevd-event[3301]: creating symlink '/dev/cd/cdrom-' to '../sr0'
Nov 17 23:27:43 proton udevd-event[3301]: '/dev/cd/cdrw-' with target '/dev/sr0' has the highest priority 0, create it
Nov 17 23:27:43 proton udevd-event[3301]: creating symlink '/dev/cd/cdrw-' to '../sr0'
Nov 17 23:27:43 proton udevd-event[3301]: '/dev/cd/dvd-' with target '/dev/sr0' has the highest priority 0, create it
Nov 17 23:27:43 proton udevd-event[3301]: creating symlink '/dev/cd/dvd-' to '../sr0'
Nov 17 23:27:43 proton udevd-event[3301]: update old symlink '/dev/cd/cdrom-4:0:0:0' no longer belonging to '/devices/pci0000:00/0000:00:1d.7/usb1/1-2/1-2:1.0/host4/target4:0:0/4:0:0:0/block/sr0'
Nov 17 23:27:43 proton udevd-event[3301]: no reference left, remove '/dev/cd/cdrom-4:0:0:0'
Nov 17 23:27:43 proton udevd-event[3301]: update old symlink '/dev/cd/cdrw-4:0:0:0' no longer belonging to '/devices/pci0000:00/0000:00:1d.7/usb1/1-2/1-2:1.0/host4/target4:0:0/4:0:0:0/block/sr0'
Nov 17 23:27:43 proton udevd-event[3301]: no reference left, remove '/dev/cd/cdrw-4:0:0:0'
Nov 17 23:27:43 proton udevd-event[3301]: update old symlink '/dev/cd/dvd-4:0:0:0' no longer belonging to '/devices/pci0000:00/0000:00:1d.7/usb1/1-2/1-2:1.0/host4/target4:0:0/4:0:0:0/block/sr0'
Nov 17 23:27:43 proton udevd-event[3301]: no reference left, remove '/dev/cd/dvd-4:0:0:0'

The right entries are removed in favour of the wrong entries and I have no idea why that is. Since I can't find the creation of this symlink anywhere in the udev scripts. I use the current udev version and the hal version from testing.

But I think it is related to this rule in 81-arch.rules:

ENV{ID_CDROM}=="?*", SYMLINK+="cd/cdrom-%b"
ENV{ID_CDROM_CD_RW}=="?*", SYMLINK+="cd/cdrw-%b"
ENV{ID_CDROM_DVD}=="?*", SYMLINK+="cd/dvd-%b"
ENV{ID_CDROM_DVD_R}=="?*", SYMLINK+="cd/dvd-%b"

The variable %b is missing. Where does this rule file gets its variables?

Last edited by tehabe (2008-11-18 20:03:30)

tehabe

Member

Registered: 2008-10-14

Posts: 82

Re: [solved] DVD/CD Device Problems/Wrong Symlinks to the Right Place

I just found out that this is only the case when there is a disc in the DVD drive. When the drive is empty all symlinks are correct.

tehabe

Member

Registered: 2008-10-14

Posts: 82

Re: [solved] DVD/CD Device Problems/Wrong Symlinks to the Right Place

This is a bug in testing/udev 132-1. In core/udev it works perfectly.

See http://bugs.archlinux.org/task/12177

Last edited by tehabe (2008-11-20 06:50:25)

mikko_v

Member

Registered: 2008-05-30

Posts: 2

Re: [solved] DVD/CD Device Problems/Wrong Symlinks to the Right Place

I'm having exactly the same problem, /dev/cd symlinks are ok when attaching the external CD drive, but break when inserting a CD. In the bug thread you say that this is a kernel problem, are you able to fix this by changing your kernel config somehow? I'm using udev-135-1 and a vanilla 2.6.28.3 kernel (self configured and compiled). Or should I edit my udev rules?

tehabe

Member

Registered: 2008-10-14

Posts: 82

Re: [solved] DVD/CD Device Problems/Wrong Symlinks to the Right Place

I solved this problem by not using any other kernel than the official stock kernel. Other kernels simply don't work. I hope this will be fixed soon, it is annoying.