CMedia CM9739 - sneaked in via some cheap via motherboards

CMedia CM9739 - sneaked in via some cheap via motherboards

[Luke Kenneth Casson Leighton]

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okay.

some of the cheapest and yet not nastiest motherboards are beginning
to become available, in the UK for £12 (KM400 chipsets) www.ebuyer.com.

some of these contain CMedia CM9739 sound chips which are _supposed_ to
be AC97.

http://www.uwsg.iu.edu/hypermail/linux/kernel/0302.3/1283.html

... except the present (2.6.7) kernel code doesn't work.

it _almost_ works - it just doesn't recognise the PCM slider.
alsamixer can't set PCM
kmix and kamix don't even _show_ PCM.

which ain't much cop, really, cos no PCM means "no sound matey".

so!

with these chipsets likely to become more prevalent (trust me
on this) and CMedia having an OSS AC97 driver [which according to above
by alan differs from the linux one]...

... anyone want to have a go at helping me get this to work,
at proxy?

if so, what sort of information should i provide?

i can get lspci's, listings of /proc/asound contents, i'm even
reasonably incompetent (viz. "not enough fear") at hacking
bits of kernel code.


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Re: CMedia CM9739 - sneaked in via some cheap via motherboards

[Alan Cox]

On Gwe, 2004-09-10 at 23:21, Luke Kenneth Casson Leighton wrote:
> it _almost_ works - it just doesn't recognise the PCM slider.
> alsamixer can't set PCM
> kmix and kamix don't even _show_ PCM.
> 
> which ain't much cop, really, cos no PCM means "no sound matey".

If I remember rightly the PCM on these is mute only. We fixed that for
OSS it may be it didnt get propogated into ALSA or this is some new
horrible variant. What we don't have is a fast software volume control
in OSS, dunno if ALSA has one.

Re: CMedia CM9739 - sneaked in via some cheap via motherboards

[Luke Kenneth Casson Leighton]

On Fri, Sep 10, 2004 at 10:46:04PM +0100, Alan Cox wrote:
> On Gwe, 2004-09-10 at 23:21, Luke Kenneth Casson Leighton wrote:
> > it _almost_ works - it just doesn't recognise the PCM slider.
> > alsamixer can't set PCM
> > kmix and kamix don't even _show_ PCM.
> > 
> > which ain't much cop, really, cos no PCM means "no sound matey".
> 
> If I remember rightly the PCM on these is mute only. We fixed that for
> OSS it may be it didnt get propogated into ALSA or this is some new
> horrible variant. What we don't have is a fast software volume control
> in OSS, dunno if ALSA has one.

 oh dearie me, well this chip _is_ listed as an         ac97->id == 0x434d4961
 and no the sound ain't working.

 i'm going to pretend it does have PCM, see what happens...

 l.

Re: CMedia CM9739 - sneaked in via some cheap via motherboards

[Luke Kenneth Casson Leighton]

On Sat, Sep 11, 2004 at 11:52:52AM +0100, Luke Kenneth Casson Leighton wrote:

> > If I remember rightly the PCM on these is mute only. We fixed that for
> > OSS it may be it didnt get propogated into ALSA or this is some new
> > horrible variant. What we don't have is a fast software volume control
> > in OSS, dunno if ALSA has one.
> 
>  oh dearie me, well this chip _is_ listed as an         ac97->id == 0x434d4961
>  and no the sound ain't working.
> 
>  i'm going to pretend it does have PCM, see what happens...
 
 thanks alan because i wouldn't have known to look for the PCM switch
 if you hadn't mentioned it.


 my sincere apologies for taking up people's time on this one:
 
 a CMedia 9739 on a VIA V8235 motherboard _is_ supported...

 ... using kmix you just have to remember to flick all of the
 pretty little lights on, including the PCM "switch" which is
 of course on a different page.

 the defaults for aaaallllll switches and i mean every single one
 is yep, you guessed it: off.

 switch them on, and it works hunky-dory.


 the only thing i _would_ mention that's useful info is that
 i've set dxs_support=4 for the snd_via_82xx module: i notice
 some syslog comments asking people to report this one.

 l.


-- 
--
Truth, honesty and respect are rare commodities that all spring from
the same well: Love.  If you love yourself and everyone and everything
around you, funnily and coincidentally enough, life gets a lot better.
--
<a href="http://lkcl.net">      lkcl.net      </a> <br />
<a href="mailto:lkcl@lkcl.net"> lkcl@lkcl.net </a> <br />