SYMLINK+="xxx" can only be used once

SYMLINK+="xxx" can only be used once

[Yan Seiner]

I'd like to know if this is a bug or a feature.  I know it's driving me 
nuts.

I have a system with 3 sound cards.  I need to assign fixed device names 
to these cards.  I've tried various combinations of module parameters 
and I've found the most reliable way is to use udev to symlink the 
device names using udev.

Here's the rule I am using:

#Yamaha Corporation YMF-724F

SYSFS{device}="0x000d", SYSFS{vendor}="0x1073", MODE="0660", 
NAME="snd/%k", SYMLINK+="soundcard/Yamaha_YMF_724F", SYMLINK+="dsp01"

What happens is that only the last SYMLINK is created.  This is 
reproducilble; I can turn the order around and the soundcard link will 
be created but not the dsp one.

I can't find any examples of multiple SYMLINK creation, so I suspect 
this may be a feature, but I don't quite understand why it would be so.

Can anyone shed some light on this?

Thanks,

--Yan

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CIDÞVDEV
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel

Re: SYMLINK+="xxx" can only be used once

[Alexander E. Patrakov]

Yan Seiner wrote:
> SYSFS{device}="0x000d", SYSFS{vendor}="0x1073", MODE="0660", 
> NAME="snd/%k", SYMLINK+="soundcard/Yamaha_YMF_724F", SYMLINK+="dsp01"
> 
> What happens is that only the last SYMLINK is created.

The documented udev rule syntax would be:

SYSFS{device}="0x000d", SYSFS{vendor}="0x1073", MODE="0660",
NAME="snd/%k", SYMLINK+="soundcard/Yamaha_YMF_724F dsp01"

(i.e., separate the names of the wanted symlinks by spaces). But, due to the 
nature of ALSA, the symlinks are not really usable because ALSA library 
never looks at them.

-- 
Alexander E. Patrakov

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CIDÞVDEV
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel

Re: SYMLINK+="xxx" can only be used once

[Yan Seiner]

Alexander E. Patrakov wrote:
> Yan Seiner wrote:
>> SYSFS{device}="0x000d", SYSFS{vendor}="0x1073", MODE="0660", 
>> NAME="snd/%k", SYMLINK+="soundcard/Yamaha_YMF_724F", SYMLINK+="dsp01"
>>
>> What happens is that only the last SYMLINK is created.
>
> The documented udev rule syntax would be:
>
> SYSFS{device}="0x000d", SYSFS{vendor}="0x1073", MODE="0660",
> NAME="snd/%k", SYMLINK+="soundcard/Yamaha_YMF_724F dsp01"
Thanks!

(Where is this documented?  I thought I went through all of the docs...  
I must have missed something.)
>
> (i.e., separate the names of the wanted symlinks by spaces). But, due 
> to the nature of ALSA, the symlinks are not really usable because ALSA 
> library never looks at them.
>

The apps I need to use still use OSS emulation - will that work?

I'm struggling a bit since sound cards have all sorts of mixers, dsps, 
etc. and I need to make sure the soundcard device names don't move 
around so the sound comes from the right set of speakers....  The 
soundcard/ symlinks are just mnemonics for me so I know what hardware I 
am dealing with, but obviously the dsp stuff I need to use.

If I create a name like /dev/dsp01 which has /dev/snd/mixer2, will that 
work or will things break in weird ways?

--Yan

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CIDÞVDEV
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel

Re: SYMLINK+="xxx" can only be used once

[Bryan Kadzban]

[-- Attachment #1.1: Type: text/plain, Size: 1946 bytes --]

On Tue, Feb 27, 2007 at 09:11:19AM -0800, Yan Seiner wrote:
> Alexander E. Patrakov wrote:
> >
> > (i.e., separate the names of the wanted symlinks by spaces). But, due 
> > to the nature of ALSA, the symlinks are not really usable because ALSA 
> > library never looks at them.
> >
> 
> The apps I need to use still use OSS emulation - will that work?

No.  The symlink you're creating here will point at the Alsa device, not
the OSS emulation device.

You have two options.  First, you could install alsa-oss and run the
programs under aoss; aoss preloads a library that converts the OSS calls
into their Alsa equivalents.

Second, you could load snd-pcm-oss and use the /dev/dsp* devices
directly.  (You can also create symlinks that point at these OSS devices
if you need to; that will work.)  Something like this might work for the
symlinks, assuming vendor and device (and whatever else) are attributes
of some parent of the /class/*/dsp* kobjects (you can use udevinfo to
find out):

KERNEL=="dsp*", ATTRS{vendor}=="whatever", etc., SYMLINK+="soundcards/BLAH"

That way you'd get a soundcards/BLAH symlink pointing at the /dev/dsp
device (and /dev/dsp1, /dev/dsp2, etc.).  The dsp* devices won't be
stable, but the symlinks will be.  If you need stable dsp* devices,
you'll have to use the "index" module parameter for each of your
drivers, and hopefully you don't have two cards sharing a driver.

> If I create a name like /dev/dsp01 which has /dev/snd/mixer2, will that 
> work or will things break in weird ways?

Well, first, DSP devices are not mixers.  So creating a symlink named
/dev/dsp01 that points at a mixer isn't that great of an idea.

But second, that's the Alsa mixer device, not the OSS mixer.  If your
programs use the OSS mixer interface, they'll need to use a symlink
pointing at /dev/mixer*, not /dev/snd/mixer*.  In short: Forget about
/dev/snd if your programs use OSS.


[-- Attachment #1.2: Type: application/pgp-signature, Size: 189 bytes --]

[-- Attachment #2: Type: text/plain, Size: 345 bytes --]

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

[-- Attachment #3: Type: text/plain, Size: 226 bytes --]

_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel