On 2021-07-29 17:05:23 +0200, Michael Biebl wrote: > Am 29.07.21 um 16:33 schrieb Vincent Lefevre: > > On 2021-07-29 16:20:48 +0200, Michael Biebl wrote: > > > And the comment from 2017 still holds true: > > > https://lists.debian.org/debian-user/2017/04/msg00790.html > > > > > > " > > > See the comment in there: > > > > > > # These rules will create symlinks for CD/DVD drives, to help old > > > # programs which are unable to automatically discover the devices. > > > # The first detected device gets the symlink, but this is not stable > > > across > > > # reboots. > > > > > > So, yes, what you see can happen depending on the order devices are > > > discovered. > > > " > > > > > > The kernel hasn't changed. It still probes devices asynchronously. > > > There is not much we can do about that. > > > > The comment says: "The first detected device gets the symlink". > > If this were true, all symlinks would be the same (even though > > this would not be stable), which is not the case. > > > > BTW, aren't the devices numbered 0, 1, etc. in the order they are > > detected, so that one would expect always sr0 here? > > It appears you do not believe what I said. Feel free to propose a patch.
This is not a question of belief, but of logic. Either sr0 or sr1 is the first detected device. Thus the 3 symlinks added by 80-debian-compat.rules are expected to be the same (possibly different from "sr0", which is hardcoded to "sr0" in 60-cdrom_id.rules). On the second remark, actually the kernel logs make this quite clear: cventin:~> journalctl -b | grep 'sr[01]' Jul 29 14:25:46 cventin kernel: sr 2:0:0:0: [sr0] scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray Jul 29 14:25:46 cventin kernel: sr 3:0:0:0: [sr1] scsi3-mmc drive: 48x/12x writer dvd-ram cd/rw xa/form2 cdda tray Jul 29 14:25:46 cventin kernel: sr 2:0:0:0: Attached scsi CD-ROM sr0 Jul 29 14:25:46 cventin kernel: sr 3:0:0:0: Attached scsi CD-ROM sr1 and ditto for the previous boots. So there are no visible issues with the kernel, only with udev. I'm not sure how this works, but if I understand the udev(7) man page correctly, I suppose that the sr number should be subtracted from the link_priority value, so that sr0 will get the precedence over sr1. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
