Re: regression in HDA functionality

Quoting fluffles.net <bsd_at_fluffles.net> (from Mon, 06 Oct 2008  
08:07:29 +0200):

> Daniel O'Connor wrote:
>> It seems that a lot of new systems now have multiple sound outputs
>> (because they use HDA) so there needs to be some way to elect a default
>> sound output (override by sysctl of course :)
>>
>> eg selecting the HDMI output is pointless if there is no HDMI link
>> active (can you detect HDMI status?)
>>
>
> Hi all,
> I'm not a dev, but may have an idea.
>
> As i understand, the problem is that with the new patch, more devices
> are detected which changes the numbering of the pcm devices, thus
> out-of-the-box sound output does not (always) work.
>
> Maybe a solution would be to *always* register pcm0, so it becomes the
> default device. This device is not a real device but rather a virtual

We have /dev/dsp, which points by default to the first registered soundcard.

> device like a wrapper/link to one of the other "real" pcm devices
> starting with pcm1. An algoritm could select which device pcm0 points
> to, and be changeable in sysctl, defaulting to "auto" or something. The

The default I wrote above, can be changed with a sysctl. You specify  
the device number (0 for pcm0, 1 for pcm1, ...). So except for one  
part (auto), we already have what you suggest.

The difficult part is the "auto". What's the right thing to choose?  
Think a little bit about it, what's right for one person is wrong for  
another one. A person which has everything connected digitally wants  
the digital by default for sure, but a person which has analog and  
digital connected, can not get a mind reading machine to see a  
sensible default. And what about those which have the soundcard  
connected to an amplifier, and the graphic card also offers the HDMI  
sound channel to the screen? Does this person want the sound only via  
the amplifier, or does he want it via the build-in speakers of the  
screen (he may want the normal stuff routed to the screen, but at some  
point turn on the amplifier and use it instead)?

> auto setting could even be extended to change default device if
> situation changes, like a new USB Audio device is plugged in or the
> headphones-output is used. It might be hard to correctly predict the
> desired behavior for everyone, but getting default audio output (front
> speakers; stereo) to work out-of-the-box would be great.

So everytime I connect an USB Audio device it means I want to switch  
to it? Maybe it's a headset and I only want to make phone calls with  
it (by telling the phone application to use specific devices), but for  
the rest I want to use the already existing sound output.

Bye,
Alexander.

-- 
Save the bales!

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