Aaugh! Sound devices changed again!

[Robin Laing]

On 2015-09-02 16:10, jdow wrote:
> On 2015-09-02 05:20, Ian Malone wrote:
>> On 2 September 2015 at 12:27, Tom Horsley <horsley1953 at gmail.com> wrote:
>>> Every single fedora release, and sometimes even just from
>>> an update where there wasn't a full release, the sound
>>> devices get renumbered or renamed. The last time I
>>> tried to play a movie and send the sound to the optical
>>> output connected to my receiver, this worked:
>>>
>>> pacmd set-card-profile 1 off
>>> mplayer -vo gl_nosw -ao alsa:device=hw=1.1 -ac hwdts,hwac3,
>>> -monitoraspect 16:9 -fs "$@"
>>>
>>> I tried it last night for the first time in a while, and
>>> it doesn't work. I've had to fiddle this script over and
>>> over again every time sound devices change.
>>>
>>> When are we going to get immutable names for sound devices?
>>> If they can do it for ethernet ports, surely they can
>>> do it for sound cards, right? (Though come to think of it
>>> the "immutable" ethernet port names change in every release
>>> as well :-).
>>>
>>
>> cat /proc/asound/cards
>>   0 [PCH            ]: HDA-Intel - HDA Intel PCH
>>                        HDA Intel PCH at 0xf6420000 irq 82
>>   1 [NVidia         ]: HDA-Intel - HDA NVidia
>>                        HDA NVidia at 0xf6080000 irq 36
>>
>> The text in [] can be used as an alsa device name. You can still add
>> the "," for sub devices.
>
> There is a basic problem here. Cheap USB audio devices tend to behave
> "cheap". They have no distinguishing features between the dongles. And
> they are not always found in the same order when you reboot the machine
> despite their USB address not changing. I have seen this with USB sound
> dongles, MIDI dongles, and DVB dongles (as used for ultra cheap SDRs.)
>
> The only solution is to develop a tool that can change serial numbers or
> other identification in the dongles, if an eeprom facility is present,
> or relying on the user never changing the USB address. In the latter
> case the name could be followed by " 0/2/4/6" or "0246" for the USB
> address path though root hub and intermediate hubs to the final device.
>
> Sounds kludgey? Yup. But it can work. Meantime it's not useful to
> purchase two or three of the same dongle in many cases. Purchase
> completely differnet dongles. They may have different names and can
> distinguish themselves that way.
>
> {^_^}

At least in KDE, you can set a priority for devices.  This allows me to 
use a USB gaming headset and it will disable the internal sound card, 
just as if I had plugged into a headphone jack.

Robin