[Bug 47706] Re: snd_nm256 module in dapper broken. Does not include oss sound module nm256_audio

pwii peter.willaert at mail.com
Sun Nov 25 13:58:11 UTC 2007

Hi Danny, Fern,

Thx for joining me on this journey. I tried unblacklisting by changing the
file /etc/modprobe.d/blacklist-oss which is a link to a file in /lib.  Upon
doing the proposed modprobe, I get an error "FATAL: module not found".
Apart from that, it looks strange to me that in the indicated file, ALL
devices are blacklisted, even the ones that get loaded anyway, like opl3 and
cs4232.  So there must be other mechanisms at work.

I would therefore try to approach this logically, trying to find out what is
loaded in when and on what hardware tests the software is deciding to do
certain things. I know that the correct chip is listed by lspci:

01:00.1 Multimedia audio controller: Neomagic Corporation NM2200 [MagicMedia
256AV Audio] (rev 20)

The excellent but unfortunately outdated article on
me that indeed this chip is a combination of various hardware blocks
that each can have their own driver.  So it makes sense to me that after a
standard boot, a lot of modules get loaded that refer to these drivers, like
opl3 and cs4332. What I don't understand is the mix of ALSA type drivers
(snd) and references to OSS which is an older sound environment. So actually
I don't know why for my Omnibook 4150 machine the boot sequence does what it
does, and most importantly, why dmesg gives me a "blacklisted 256, loading
stopped" error butI still get the other drivers loaded (which part of the
software does that, and based on what configuration info)?

 And of course at this point I have no sound, and when I try 'alsamixer' I
only get a reference to a default device.  This leads me to the idea that
somehow the configuration is at fault, i.e. the drivers are not looking to
the right location (in ALSA, apparently, a lot of coexisting sound cards are
possible).  But what I am missing also are some simple tools that kind of
would try to show the complete audio chain: chip - drivers - high end
drivers, showing me where the thing is broken. A lot of drivers are listed,
but are they actually used?? depmod is only of limited use.

The ALSA doc is not very helpful to me, because the ALSA drivers are
included in the 2.6.22 kernel, so downloading/building in the ALSA stuff is
probalby not needed at all.  But maybe there is still something in utils or
lib (from ALSA) that might be of help? (I didn't try) Furthermore when it
comes to configuration, the whole ALSA doc gets me seriously lost.

Does this concur with your own findings/reasonings so far? Or am I missing
out on something?

Thanks for any meaningful, non-black-magic input!


On Nov 25, 2007 1:07 AM, Danny Staple <danny at orionrobots.co.uk> wrote:

> Hi Fern,
> As the poster pwii mentioned, you need to remove the entry (or comment
> out)
> in /etc/modprobe.d/blacklist-oss.
> You should note that as Lee Revell mentioned, this module could
> potentially
> lead to system lock ups - have a rescue CD handy to add the module back
> into
> the blacklist if it does not work.
> Cheers,
> Danny
> On 24/11/2007, fern <fernmarques at yahoo.com> wrote:
> >
> > Hi, Danny
> >
> > I want to try this, too, but what is "unblacklisting",
> > and how do I do it?
> >
> > Thanks
> >
> > Fern
> >
> >
> > --- Danny Staple <danny at orionrobots.co.uk> wrote:
> >
> > > OTOH - Abbreviation for "On The Other Hand"..
> > >
> > > After unblacklisting, you might get away with simply
> > > inserting the module
> > > again, with no reboot. Try this on the command line:
> > > "modprobe nm256_audio"
> > >
> > > Then check dmesg.
> > >
> > > Cheers,
> > > Danny
> > >
> > > On 24/11/2007, pwii <peter.willaert at mail.com> wrote:
> > > >
> > > > I don't know what OTOH is...
> > > >
> > > > unblacklisting nm256, is that in
> > > /etc/modprobe.d/blacklist-oss
> > > > [nm256_audio]
> > > > ?
> > > >
> > > > I guess after unblacklisting I will need to
> > > reboot.
> > > >
> > > > Thx again -- Peter
> > > >
> > > >
> [...]

snd_nm256 module in dapper broken. Does not include oss sound module nm256_audio
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