Bug#606482: no headphone output on ASUS M4A785T-D motherboard

2012-02-25 Thread Jonathan Nieder
Sergio Gelato wrote:

> The problem turned out to be due to an inappropriate BIOS configuration
> setting. The "Front Panel Select" setting needed (for my specific case)
> to be set to "AC97" instead of "HD Audio". Found thanks to some comments in
> https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5309
> (especially note 23449).
>
> No kernel changes needed.

That sounds like a workaround rather than a fix.

If it is possible to get the headphone jack working in HDA mode as well
as AC97, we would like to do that, to avoid new users having to learn what
BIOS knob to change.  Based on the upstream report you mentioned it
seems that 2.6.39 might fix this; could you try 3.2.y from wheezy or
unstable?  (The only packages needed from outside squeeze for this
test are the kernel image itself, linux-base, and initramfs-tools.)

Thanks for the update,
Jonathan



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Bug#606482: no headphone output on ASUS M4A785T-D motherboard

2012-02-27 Thread Sergio Gelato
* Jonathan Nieder [2012-02-25 21:19:43 -0600]:
> Sergio Gelato wrote:
> 
> > The problem turned out to be due to an inappropriate BIOS configuration
> > setting. The "Front Panel Select" setting needed (for my specific case)
> > to be set to "AC97" instead of "HD Audio". Found thanks to some comments in
> > https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5309
> > (especially note 23449).
> >
> > No kernel changes needed.
> 
> That sounds like a workaround rather than a fix.

I don't see it that way: my front panel is in fact of the older AC97 type,
so the earlier BIOS setting was incorrect and changing it was the proper
thing to do.

When I installed this motherboard I wasn't sure whether I had HDA or AC97,
so I decided to try one setting and see if it worked. The fact that the
Ubuntu 10.04 kernel appeared to work even with the setting I tried first
actually made it harder for me to correctly diagnose the problem.

> If it is possible to get the headphone jack working in HDA mode as well
> as AC97, we would like to do that, to avoid new users having to learn what
> BIOS knob to change.

That way lies madness. Maybe in this particular instance one can get away with 
it, but in general this approach will add complexity to the software. 
It's already bad enough to have to work around hardware bugs.

My impression so far is that the newer HDA front panels allow better power
management and that the driver change that apparently broke headphone sound
for me was actually an enhancement to make better use of the capabilities of
HDA. So of course one can revert to the older approach, but then one
probably loses some benefits of the newer one. One could add a kernel 
(module) option to control this, but then the user needs to figure out what 
setting is needed and it's just as easy to find out about the BIOS switch 
instead.

My preferred approach would be to add this to the troubleshooting guides:
if your audio front panel is misbehaving, check that it is of the right type
for your motherboard. (Probably with some additional words about AC97 vs.
HDA and/or a link to an external reference.)

Now, if there was a way for the kernel to detect a misconfigured front panel
and issue a warning in dmesg that would be great. I have no idea whether that
is feasible.

>  Based on the upstream report you mentioned it
> seems that 2.6.39 might fix this; could you try 3.2.y from wheezy or
> unstable?  (The only packages needed from outside squeeze for this
> test are the kernel image itself, linux-base, and initramfs-tools.)

The reason I revisited this bug now is that I tried 3.2.0-0.bpo.1 (for
other reasons) and found that the headphone functionality was still
broken. That prompted me to make a new search through the ALSA knowledge 
base, which yielded the hint about the two types of front panel. The
report I found the hint in ended up addressing some other issue.

> Thanks for the update,
> Jonathan



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Bug#606482: no headphone output on ASUS M4A785T-D motherboard

2012-02-27 Thread Ben Hutchings
On Mon, 2012-02-27 at 09:06 +0100, Sergio Gelato wrote:
> * Jonathan Nieder [2012-02-25 21:19:43 -0600]:
> > Sergio Gelato wrote:
> > 
> > > The problem turned out to be due to an inappropriate BIOS configuration
> > > setting. The "Front Panel Select" setting needed (for my specific case)
> > > to be set to "AC97" instead of "HD Audio". Found thanks to some comments 
> > > in
> > > https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5309
> > > (especially note 23449).
> > >
> > > No kernel changes needed.
> > 
> > That sounds like a workaround rather than a fix.
> 
> I don't see it that way: my front panel is in fact of the older AC97 type,
> so the earlier BIOS setting was incorrect and changing it was the proper
> thing to do.
> 
> When I installed this motherboard I wasn't sure whether I had HDA or AC97,
> so I decided to try one setting and see if it worked. The fact that the
> Ubuntu 10.04 kernel appeared to work even with the setting I tried first
> actually made it harder for me to correctly diagnose the problem.

AC97 and HDA are specifications for the interface from the PCI(e) bus to
the sound chip.  Some chips support both interfaces, either at the same
time or selected by firmware (BIOS setting).

[...]
> My preferred approach would be to add this to the troubleshooting guides:
> if your audio front panel is misbehaving, check that it is of the right type
> for your motherboard. (Probably with some additional words about AC97 vs.
> HDA and/or a link to an external reference.)
[...]

The connection from the sound chip to any external connectors is
independent of such specifications; there is no such thing as an 'HDA
front panel'.  However the two specifications have different ways for
the chip/board to describe which connectors are wired to it.  The
problem you're seeing is very likely related to some oddity of the
description.

Ben.

-- 
Ben Hutchings
Q.  Which is the greater problem in the world today, ignorance or apathy?
A.  I don't know and I couldn't care less.


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Bug#606482: no headphone output on ASUS M4A785T-D motherboard

2012-02-27 Thread Sergio Gelato
* Ben Hutchings [2012-02-27 14:50:45 +]:
> On Mon, 2012-02-27 at 09:06 +0100, Sergio Gelato wrote:
> > * Jonathan Nieder [2012-02-25 21:19:43 -0600]:
> > > Sergio Gelato wrote:
> > > 
> > > > The problem turned out to be due to an inappropriate BIOS configuration
> > > > setting. The "Front Panel Select" setting needed (for my specific case)
> > > > to be set to "AC97" instead of "HD Audio". Found thanks to some 
> > > > comments in
> > > > https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5309
> > > > (especially note 23449).
> > > >
> > > > No kernel changes needed.
> > > 
> > > That sounds like a workaround rather than a fix.
> > 
> > I don't see it that way: my front panel is in fact of the older AC97 type,
> > so the earlier BIOS setting was incorrect and changing it was the proper
> > thing to do.
> > 
> > When I installed this motherboard I wasn't sure whether I had HDA or AC97,
> > so I decided to try one setting and see if it worked. The fact that the
> > Ubuntu 10.04 kernel appeared to work even with the setting I tried first
> > actually made it harder for me to correctly diagnose the problem.
> 
> AC97 and HDA are specifications for the interface from the PCI(e) bus to
> the sound chip.  Some chips support both interfaces, either at the same
> time or selected by firmware (BIOS setting).
> 
> [...]
> > My preferred approach would be to add this to the troubleshooting guides:
> > if your audio front panel is misbehaving, check that it is of the right type
> > for your motherboard. (Probably with some additional words about AC97 vs.
> > HDA and/or a link to an external reference.)
> [...]
> 
> The connection from the sound chip to any external connectors is
> independent of such specifications; there is no such thing as an 'HDA
> front panel'.  However the two specifications have different ways for
> the chip/board to describe which connectors are wired to it.  The
> problem you're seeing is very likely related to some oddity of the
> description.

If you say so. I don't claim any real expertise in this area. I do note that
http://www.intel.com/support/motherboards/desktop/sb/cs-020642.htm#standards
says in part:
"To identify your front panel audio solution’s audio codec, refer 
 to the specifications or documentation for your PC chassis or 
 front panel module. Note that AC’97 and HD Audio front panel 
 solutions are different and may not be directly compatible 
 or interchangeable."
and goes on to point out a physical wiring difference involving pin 4.



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Bug#606482: no headphone output on ASUS M4A785T-D motherboard

2012-02-29 Thread Jonathan Nieder
Sergio Gelato wrote:

> If you say so. I don't claim any real expertise in this area. I do note that
> http://www.intel.com/support/motherboards/desktop/sb/cs-020642.htm#standards

jlandonx at Intel wrote:

> You can also physically check the audio cable of the front panel audio
> solution. If there is a cable connected to Pin 4, you have an HD Audio
> module; if there is no cable to Pin 4, you have an AC97 module.

And:

> HD front panel audio solutions should be plugged into HD onboard
> headers.  AC’97 front panel audio solutions should be plugged into
> AC’97 onboard headers.  Some AC’97 front panel audio solutions (but
> not all) may work with HD onboard headers.  If you want connect an
> AC’97 front panel audio system to HD onboard headers, try these steps:
>
>   Connect Mic_IN (MIC) to MIC2_L.
>   Connect Audio_R (RIN) to OUT2_R
>   Connect Audio_L (LIN) to OUT2_L.
>   MIC_RET and OUT_RET are for HD audio only; you don't need to connect
>   them for AC'97 audio.
>
> Intel does not validate AC’97 front panel audio solutions with boards
> using HD audio. If the steps above do not work, you will need to use
> an HD front panel audio solution for full compatibility with Intel
> Desktop Boards using Intel 945 chipsets and later.

I don't know if there's a way for the BIOS to automatically detect the
front panel type, but now we're way out of kernel land, so yes, that
doesn't make it sound like a major kernel bug. ;-)

However, it seems odd to me that an older kernel (from Ubuntu 10.04)
worked fine.  Doesn't that suggest there might be a possible
workaround?  Maybe as suggested in [1] this is a jack sense problem
and 1731437 (ALSA: HDA VIA: Add low current mode for power saving.,
2009-10-10) triggered trouble and if we can detect this condition all
we might need is a way to force the jack to power up.

Curious,
Jonathan

[1] https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5309#c23449



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