[pulseaudio-discuss] ACLs for USB devices on Debian GNU/Linux Squeeze/testing

[Frode Severin Hatlevik]

2010/8/19 Colin Guthrie <gmane at colin.guthr.ie>:
> 'Twas brillig, and Tomasz Torcz at 19/08/10 18:20 did gyre and gimble:
>> On Thu, Aug 19, 2010 at 06:15:26PM +0100, Colin Guthrie wrote:
>>>
>>>> It turned out to be quite
>>>> simple. I only needed to add a file, say 60-sound.rules containing the
>>>> following line:
>>>> SUBSYSTEM=="sound", ENV{ACL_MANAGE}="1"
>>>>
>>>> Then I issued "udevadm trigger" and things started working.
>>>>
>>>> It is important to note that this rule should be numbered below 70, as
>>>> the standard udev rule dealing with ACL is
>>>> /lib/udev/rules.d/70-acl.rules
>>>> at least on my Debian Squeeze/testing. Thus the matching needs to be
>>>> done prior to the execution of this rule.
>>>
>>> Hmm, strange.. I'm not sure what your /lib/udev/rules.d/70-acl.rules has
>>> in it but mine has:
>>> [colin at jimmy udev]$ grep sound.*ACL_MANAGE /lib/udev/rules.d/70-acl.rules
>>> SUBSYSTEM=="sound", ENV{ACL_MANAGE}="1"
>>> SUBSYSTEM=="input", SUBSYSTEMS=="sound", ENV{ACL_MANAGE}="1"
>>>
>>>> I will file this as a bug in Debian BTS. Should this udev-trick be
>>>> included in the guide for packaging PA?
>>>
>>> Well from what I can tell the official 70-acl.rules has this line in it
>>> already.... (certainly in udev-153 but I'm pretty certain it's been like
>>> this for a while).
>>>
>>> Not sure if you're Debian version is altered or something but it smells
>>> like a debian specific bug.
>>
>>   Debian udev maintainer insist on creating own rules instead of using
>> upstream ones.
>
> <sarcasm>Awesome.</sarcasm>
>

I suppose the Debian maintainer has his reasons for doing so. Debian
is famous for making adjustments to all sorts of packages, ranging
from the Linux kernel, with specific Debian patches, to userland libs
and programs. This, I understand, is partly in order to make all
software in the main repository adhere to the Debian Free Software
Guidelines, and partly to provide a system that is maintainable in
terms of using the Debian packaging system.

The DFSG is available at http://www.debian.org/social_contract. I am
informed that the DFSG has been a major inspiration for other works,
such as The Open Source Definition,
http://www.opensource.org/docs/definition.php.

Anyways, trying to maintain a distribution such as Debian is bound to
make some problams, such as the one I was experiencing. Now, I am
using the Squeeze/testing distribution. This is not a released Debian
distribution, but one under active development. I'll give the
maintainers an update about the issue I am experiencing, and hopefully
there will be a fix before Squeeze releases.

Anyways, on my system:
frode at reepicheep:~$ sudo udevadm --version
160
frode at reepicheep:~$ grep sound.*ACL_MANAGE /lib/udev/rules.d/70-acl.rules
frode at reepicheep:~$

Moreover, here are some snippets form /lib/udev/rules.d/70-acl.rules
# do not edit this file, it will be overwritten on update

# Do not use TAG+="udev-acl" outside of this file. This variable is private to
# udev-acl of this udev release and may be replaced at any time.
<snip />
# sound devices
SUBSYSTEM=="sound", TAG+="udev-acl"
# sound jack-sense
SUBSYSTEM=="input", SUBSYSTEMS=="sound", TAG+="udev-acl"
<snip />

I suppose these rules are meant to do the trick. Clearly, they do not
work as intended. I will do some more testing to see what I can make
of it.

By the way, what does the line
SUBSYSTEM=="input", SUBSYSTEMS=="sound", ENV{ACL_MANAGE}="1"
from the upstream udev ruleset do? Are there separate sound devices in
the input subsystem?

;)Frode

-- 
Da sa Gud: "Det bli lys!"
Og det ble lys.
                      1. Mosebok 1.3

And God said, "Let there be light,"
and there was light.
                      Genesis 1:3, NIV