[alsa-devel] force snd-usb-audio to use "Vendor Specific Class"

[Alexey Fisher]

Am Donnerstag, den 24.06.2010, 12:36 +0200 schrieb Hans de Goede:
> Hi,
> 
> On 06/23/2010 03:29 PM, Alexey Fisher wrote:
> > Hallo all,
> > is there any way to force snd-usb-audio to use some "Vendor Specific
> > Class" device?
> > i currently got two webcams from my friends to take a look on. They are
> > cheep gspca based webcams with Mic. I wont to test if snd-usb-audio can
> > use it if i force it. Devices it self do not provide any hints for the
> > driver.
> >
> > lsusb -vd 093a:2468 | grep -i class
> >    bDeviceClass          255 Vendor Specific Class
> >    bDeviceSubClass       255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >        bInterfaceClass       255 Vendor Specific Class
> >        bInterfaceSubClass    255 Vendor Specific Subclass
> >
> > regards,
> > Alexey
> >
> 
> 
> Don't bother, AFAIK these devices which are pixart pac207bca
> based do not contain any microphone at all. If they do they usually
> have 2 plugs at the end of their cable a usb plug and an analog
> one for the mic.
> 
> Google for pac207bca datasheet to find a useless datasheet, note
> that it does contain a listing of the physical pins of the device,
> and notice the lack of any pins to connect a microphone too.
> 
> If the pac207 supports a microphone (which I strongly believe
> it does not) the mic on these cameras is not a usb audio class
> compatible device. The pac207 declares only one interface so
> audio data ihas to be handled over the same interface
> as the video data. So in order to support the MIC you first need to
> find out how it works and then glew an alsa driver onto the
> gspca pac207 driver (as only one driver can be bound to a single
> usb interface).
> 
> Regards,
> 
> Hans, the pac207 driver maintainer
> 
> 
> p.s.
> 
> It would have been helpful if you had contacted me about this, I just
> happen to be subscribed to the alsa-devel list too.

Thank you for your response,
i buried this cam yesterday.
after some hours of useless hacking i went to "Trust" web page and
checked documentation. After i didn't found anything about sound i
extracted the driver and didn't found anything about sound ether. Then i
took windows and tested this cam... and ... no sound.
Memo on me: check documentation before wast time :/

Regards,
Alexey Fisher