[pulseaudio-discuss] M-Audio FastTrack Pro

[Lennart Poettering]

On Thu, 07.01.10 17:31, David Kågedal (davidk at lysator.liu.se) wrote:

> >> Sure, I will do that. But I'm still not sure I understand why we aren't
> >> using then perfectly good name "M-Audio FastTrack Pro" that apparently
> >> is reported by ALSA in /proc/asound/cards.
> >
> > See Lennart's point 3 above. In *your* case it's nice, but apparently in
> > the majority of cases it's not nice and totally generic which is no use
> > to anyone.
> 
> Yes, the USB information is nice for me. But PA shows a broken string
> that it seems to have invented itself. So far, nobody has been able to
> explain why it does that (until you gave a suggestion below). If it had
> simply used the USB information, I would have been happy.

You maybe., most others not. It is a simple fact that most
manufacturers dont give teh USB descriptor data the love it deserves,
e.g. very seldomly the USB serial id is actually useful.

The USB descriptor data is available via sysfs
(/sys/bus/usb/devices/*-*/manufacturer and
/sys/bus/usb/devices/*-*/product). If you check that you will notice
that very often the data in those fields is not exactly useful if it
is available at all (in which case those files wont exist)

> > These two ultimately come from UDEV:
> >
> > udev_device_get_property_value(card, "ID_MODEL_FROM_DATABASE")
> >  and
> > udev_device_get_property_value(card, "ID_SERIAL")
> >
> > So I guess udev puts the underscores in.
> 
> Thank you. Finally a pointing finger.
> 
> So why is udev giving us a mangled name? And why is PA using that,
> rather than using the information it obviously can get from the device?

Because we trust udev. And we want to keep the bus-specific code in PA
at a minimum.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4