Re: Problem with Avermedia 771

[Takashi Iwai <tiwai@suse.de>]

At Tue, 19 Oct 2004 18:13:40 +0200,
Gerd Knorr wrote:
> 
> > >   (1) The ones where you can get audio data out of PCI function .1
> 
> > >   (4) Cards where PCI function .1 is simply unused, i.e. you get either
> > >       nothing or just noise if you try to record audio from there.
> 
> > > I think the alsa driver should only try to use cards which fall into
> > > group (1), not everything but (2).  Problem with that is that it simply
>                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > isn't known for most cards whenever they are in group (1) or (4).
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> > I see the device list in drivers/media/video/bttv-cards.c as mentioned
> > in Gerd's original post.  Which ones can be as the white list entries
> > for ALSA?
> 
> Well, the problem is that no such list exists right now, I didn't keep
> track of whenever Function .1 can do audio or not in bttvs card database
> because bttv doesn't care, it does video only ...

Ok.

> So we'll have to build a whitelist from scratch from user feedback, and
> maybe add a insmod option so you can ask the driver to grab the device
> even if not whitelisted for easy use.

We have some options for this kind of behavior:

1. the driver has one pci_driver struct, and its pci_id array includes
   the default entries (with PCI_ANY_ID for subsystem ids).

   In this case, the driver checks the pci id in probe and rejects
   unless it's in the whitelist or a specific module option is given.

2. the driver has two pci_driver structs, one only with whitelist and
   one with the whitelist and the default entries.
   In init code, the driver registers the corresponding pci_driver
   record according to the module option.

   In this case, the driver accepts all.
   But which table should be exported via MODULE_DEVICE_TABLE?


I think 1 is the better way but my concern is about the hotplug.
Can this mechanism work with hotplug properly?  I guess yes, but
didn't take a look at any example yet...


Takashi


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