Re: hot to distinquish between 2 USB devices with same vendor and product id

[Brandon Philips <brandon@xxxxxxxx>]

On 09:22 Wed 04 Mar 2009, Belisko Marek wrote:
> Hi,
> 
> On Tue, Mar 3, 2009 at 6:41 PM, Greg KH <greg@xxxxxxxxx> wrote:
> > On Tue, Mar 03, 2009 at 11:55:24AM +0100, Belisko Marek wrote:
> >> On Tue, Mar 3, 2009 at 7:29 AM, Greg KH <greg@xxxxxxxxx> wrote:
> >> > On Mon, Mar 02, 2009 at 02:36:55PM +0100, Belisko Marek wrote:
> >> >> My problem is that during init I should setup camera with different
> >> >> init data stream but cameras
> >> >> can have same vendor and product id (but different init data should be sent).
> >
> > But if the device has the exact same descriptor, that would mean they
> > are the same type of devices, right?  If not, then the manufacturer
> > really messed up.
> 
> Yes you're right. I find those cameras with same descriptor:
> ProLink DS3303u,Plustek Opticam 500U vendor:0x06a5, product: 0xd001	
> D-link dru-350c vendor:0x06a5, product: 0xd001
> Conceptronic Video Pro 	vendor:0x06a5, product: 0xd001
> TwinkleCam vendor:0x06a5, product: 0xd001
> Mustek vendor:0x06a5, product: 0xd001
> 
> I think this is because they use same camera engine (from divio)
> but they need different init configurations (maybee because of different CCDs).
> 
> That's also very strange for me and I think it's not possible correctly
> distinguish between devices. I think I support only webcams with
> different descriptors. Then driver doesn't cover all devices ...
> egg-chicken problem ;)

There are a number of PCI video devices that have the same issue: same PCI
PID/VID but different hardware on the board. The best thing you can do is
provide a sysfs file entry to manually set the type of the device.

Hope that helps.

Cheers, Brandon

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