[linux-dvb] [PATCH] m920x for LifeView TV Walker Twin

Patrick Boettcher patrick.boettcher at desy.de
Tue Mar 20 15:13:53 CET 2007

Hi Nick,

thanks for this nice patch. I'm not in charge of committing that (don't 
know the uli-thing very well), but I would like to comment:

On Wed, 21 Mar 2007, Nick Andrew wrote:

> Here's my patch so far.
> Two remaining problems:
> 1 - device is probed twice and I end up with 4 /dev/dvb adapters
> rather than two. The reason is that the USB configuration defines
> two interfaces, so the probe function is called once for each
> interface.
> I don't yet know what to do about this. Presumably the right
> solution is to configure tuner/demod 0 on the first call to
> m920x_probe(), and tuner/demod 1 on the second call. But I don't
> know how to achieve this because all the configuring happens inside
> dvb_usb_device_init() and it's mostly hardcoded inside the @adapter
> array in dvb_usb_device_properties.
> I wrote a quick workaround (which _isn't_ in this patch) which
> detects if it is probing bInterface == 1, and if so then returns
> without probing, and that proves my analysis (only 2 adapters
> are created under /dev/dvb).

If the device is working OK like that, your workaround is good. I assume 
that the ULI/Lifeview people didn't want to spend much time to create an 
architecture for their Windows driver, which supports multiple 
BDA-filters per device. So they changed the USB-descriptor so that their 
driver is called twice so that they can do the second receiver.


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