* Re: 082 cdsymlinks
2006-01-26 19:09 082 cdsymlinks Aaron Griffin
@ 2006-01-26 19:16 ` Andrey Borzenkov
2006-01-26 20:27 ` Aaron Griffin
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Andrey Borzenkov @ 2006-01-26 19:16 UTC (permalink / raw)
To: linux-hotplug
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On Thursday 26 January 2006 22:09, Aaron Griffin wrote:
> Hello all,
> With the removal of %e in udev 082, what do you all do with your
> cdsymlinks?
>
> You can't really remove them efficiently, because quite alot of apps
> default to /dev/cdrom0 or something similar.
>
> Using a small script to attach the appropriate number (i.e. cdrom2)
> doesn't work either because udev doesn't honor any sort of device
> order, so an end user may end up placing a cd in 3 different drives to
> get xmms to play some audio, for example.
>
> I've noticed none of the 'big distros' have solved this problem yet.
> Does anyone have a solution or any ideas at all?
>
Well, I recently posted here a suggestion (with small patch) to create
persistent links for CD-ROMs in /dev/cd (actually in /dev/$env{ID_TYPE}).
This also solves the problem of pam_console - unfortunately it can match on
device name only and removing /dev/cdrom* removed also any distinguishing
name.
Having disks in /dev/disk and CD-ROMs in /dev/cd looks more logical and gives
you persistent names for CD-ROMs. See also recent discussion on lkml on how
to enumerate all available CD-ROMs :)
- -andrey
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: 082 cdsymlinks
2006-01-26 19:09 082 cdsymlinks Aaron Griffin
2006-01-26 19:16 ` Andrey Borzenkov
@ 2006-01-26 20:27 ` Aaron Griffin
2006-01-26 23:24 ` Kay Sievers
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Aaron Griffin @ 2006-01-26 20:27 UTC (permalink / raw)
To: linux-hotplug
On 1/26/06, Andrey Borzenkov <arvidjaar@mail.ru> wrote:
> Well, I recently posted here a suggestion (with small patch) to create
> persistent links for CD-ROMs in /dev/cd (actually in /dev/$env{ID_TYPE}).
> This also solves the problem of pam_console - unfortunately it can match on
> device name only and removing /dev/cdrom* removed also any distinguishing
> name.
Sorry, but I'm unable to find this posting, and I only recently
subscribed. The closest I have come is the following:
---------------------------
From: Kay Sievers <kay@vr...>
> Yuu can match on ENV{ID_PATH} with custom rules for every device. On
> SUSE, the system management creates rules on installation or update, to
> have always the same names for optical drives, regardless of the order
> of discovery:
>
> $ cat /etc/udev/rules.d/65-cdrom.rules
> # cdrom links generated by YaST2
> #
> SUBSYSTEM="block", ENV{ID_PATH}="pci-0000:00:1f.2-scsi-1:0:0:0", \
> SYMLINK+="cdrecorder cdrom"
>
> Distros could also have a "default" rule, which catches unconfigured
> devices and automatically creates a rule for them to keep the name
> stable across reboots.
---------------------------
> Having disks in /dev/disk and CD-ROMs in /dev/cd looks more logical and gives
> you persistent names for CD-ROMs. See also recent discussion on lkml on how
> to enumerate all available CD-ROMs :)
Yes, I'll agree with that, but my main issue had to do with cdrom
ordering. I can easilly cram them in /dev/cd, but I'd like
a) for them to remain in the same order, which seems to involve
ID_PATH comparissons
b) to preserve symlinks for backwards compatability, at least for some
time - /dev/cdrom{0,1,2,3,4}
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: 082 cdsymlinks
2006-01-26 19:09 082 cdsymlinks Aaron Griffin
2006-01-26 19:16 ` Andrey Borzenkov
2006-01-26 20:27 ` Aaron Griffin
@ 2006-01-26 23:24 ` Kay Sievers
2006-01-27 17:08 ` Darren Salt
2006-01-27 20:58 ` Aaron Griffin
4 siblings, 0 replies; 6+ messages in thread
From: Kay Sievers @ 2006-01-26 23:24 UTC (permalink / raw)
To: linux-hotplug
On Thu, Jan 26, 2006 at 01:09:32PM -0600, Aaron Griffin wrote:
> With the removal of %e in udev 082, what do you all do with your cdsymlinks?
%e is not removed now, it's just no longer in the man page and should be
avoided. But sure, some day I'll be happy to remove it, but we need a
simple replacement for the distros/systems that don't do centralized
management.
> You can't really remove them efficiently, because quite alot of apps
> default to /dev/cdrom0 or something similar.
>
> Using a small script to attach the appropriate number (i.e. cdrom2)
> doesn't work either because udev doesn't honor any sort of device
> order, so an end user may end up placing a cd in 3 different drives to
> get xmms to play some audio, for example.
>
> I've noticed none of the 'big distros' have solved this problem yet.
No, on SUSE YaST maintains a rule file, that matches with ID_PATH and
assigns the names for optical devices persistently.
> Does anyone have a solution or any ideas at all?
o Make a simple program, that can be used to edit a dedicated rules file
and let the user pick a device from the list and assign it a name. The
program should have simple subsystem specific knowlege, what properties
can be used for a device. So it could match on SYSFS{address} for network
interfaces and use ENV{ID_PATH} for a cdrom ...
o Or make it automatically write rules for new devices and assign them a
new name. That way you get at least everytime the same name, even when
hardware of the same class is removed from the system which would break
any simple enumeration.
o Use the persistent naming scheme to reference the devices, but that will
obviously not be cdrom, cdrom1, cdrom2.
Kay
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: 082 cdsymlinks
2006-01-26 19:09 082 cdsymlinks Aaron Griffin
` (2 preceding siblings ...)
2006-01-26 23:24 ` Kay Sievers
@ 2006-01-27 17:08 ` Darren Salt
2006-01-27 20:58 ` Aaron Griffin
4 siblings, 0 replies; 6+ messages in thread
From: Darren Salt @ 2006-01-27 17:08 UTC (permalink / raw)
To: linux-hotplug
I demand that Kay Sievers may or may not have written...
[snip]
> o Or make it automatically write rules for new devices and assign them a
> new name. That way you get at least everytime the same name, even when
> hardware of the same class is removed from the system which would break
> any simple enumeration.
... for some values of "break".
I'm thinking now, given your insistence on generated rules, that perhaps a
sequence number which does nothing more than provide the order in which the
devices should be numbered would be a Good Thing. That way, assuming
hdcÍrom and hddÍrom1 and there are no other cdrom* devices, physically
removing hdc would cause hdd to become cdrom after the next reboot - but hdb
would become cdrom2 regardless (even though this Just Feels Wrong), unless
the system was told that hdc was permanently gone.
This is a matter of compatibility: there are programs and libraries which do
things such as check only /dev/cdrom or default to /dev/cdrom: the VideoCD
input module in xine-lib defaults to /dev/cdrom, and its DVD input module
defaults to /dev/dvd.
Feel free to submit patches :->
--
| Darren Salt | d youmustbejoking,demon,co,uk | nr. Ashington,
| Debian, | s zap,tartarus,org | Northumberland
| RISC OS | @ | Toon Army
| Let's keep the pound sterling
Money can't buy you friends, but you get a better class of enemy.
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: 082 cdsymlinks
2006-01-26 19:09 082 cdsymlinks Aaron Griffin
` (3 preceding siblings ...)
2006-01-27 17:08 ` Darren Salt
@ 2006-01-27 20:58 ` Aaron Griffin
4 siblings, 0 replies; 6+ messages in thread
From: Aaron Griffin @ 2006-01-27 20:58 UTC (permalink / raw)
To: linux-hotplug
On 1/27/06, Darren Salt <linux@youmustbejoking.demon.co.uk> wrote:
> This is a matter of compatibility: there are programs and libraries which do
> things such as check only /dev/cdrom or default to /dev/cdrom: the VideoCD
> input module in xine-lib defaults to /dev/cdrom, and its DVD input module
> defaults to /dev/dvd.
The only solutions I've come up with require taking the scope outside
of udev. Keeping this compatible, at a fairly generic, non-Yast'ed
level, seems to be impossible within udev. It'd require some
execution after udev has finished, which then isn't that different
from a static /dev setup.
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^ permalink raw reply [flat|nested] 6+ messages in thread