Re: USB device getting different product ids

[Greg KH <gregkh@suse.de>]

On Tue, Aug 10, 2010 at 05:08:00PM +0200, Dhaval Giani wrote:
> Heya,
> 
> Admittedly I am using an older kernel, but I was wondering if a USB
> device can get different product ids on being plugged in at different
> times. I have one of these nice USB modems to connect to the internet
> . It is one of these huawei devices. Now, most of the times, it gets
> detected with vendor id 0x12d1 and product id 0x1446. In this mode, on
> loading the usbserial module, I see only ttyUSB0 come up, which for
> whatever reason, I am unable to use to connect to the internet.
> However when it is detected as the product id 0x140b, I get
> ttyUSB[0-2] which then connects very nicely via both wvdial and
> networkmanager to the internet. Now obviously, I would like for the
> device to get detected as 0x140b each time, as opposed to me pulling
> it out and inserting it back in till does get detected as 0x140b :-).
> 
> So my question is,
> 
> 1. Is it possible for the same device to get different product ids at
> different times

Yes, it's quite common for some devices to do this.

> 2. If so, how do I possibly get it to detect the id I want, as opposed
> to playing a game of chance.

Look at the usb-modeswitch program, it's what you want to control this.

> (I would copy linux-usb if I knew the mailing list id, but as I am on
> a slow GPRS connection, which is quite flaky right now, I would like
> to send this out right now. Please copy that list if it would help!)

In the future, it's the linux-usb@vger.kernel.org list, also available in
the MAINTAINERS file.

thanks,

greg k-h