[linux-dvb] dib0700 problems (nova-T usb stick)

Soeren Moch Soeren.Moch at stud.uni-hannover.de
Thu Jun 7 12:48:58 CEST 2007

Heh, heh, a lot of traffic on this list concerning nova-t sticks today

>> As I can see the dib0700 USB bridge in this stick deactivates the
>> I2C controller during data streaming, so all I2C accesses to mt2060
>> (tuner) and dib7000pc (dvb-t demodulator) fail. Therefore you get
>> "I2C read fails" messages from mt2060 and uninitialized (random) data
>> for the frontend (dib7000pc) status.
>> Unfortunately there seems to be no independent I2C gate control call in
>> the dib0700 firmware...
> So.. .with this hardware restriction, having a "working" driver that 
> behaves like the other devices is going to be hard?

Hmm, after half a week (1 day, 2 nights) looking on this device I don't
want to say that, maybe there is a easy solution...

> Could a fix for this be to ensure that in the driver if a tune request 
> is sent, the driver stops streaming, tunes, then starts again?

Exactly that I tried last night, it worked twice, afterwards only black
(not blue ;-) ) screens, must be a bug in my code...

> At the 
> same time the front end status could be cached from just before 
> streaming is started and this cached data returned when requested, 
> rather than going to the device itself?

Also that idea I had yesterday, but static values are not very useful
(e.g to find a optimal antenna position)...

> Both of these seem a bit like a "hack" to me, but seem like they would 
> bring the driver closer to behaving the way apps like VDR expect. If 
> there is not way of accessing the real data, then at least a cached 
> version from before streaming was started would provide some data.


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