Twinhan USB DTV dongle not working :(

so after doing some researching (read: using search engines with linux + product name), I came to the conclusion that a Twinhan USB2.0 DVB dongle would be the dongle for me. Yes – it’s small, compact and does digital tv without requiring a non-existant free PCI slot in my Shuttle MythTV box.

Having had great success with my last bit of new hardware (a really cheap Logitech QuickCam Express or something) – plug it in and it “just works”. Oh Linux how you are better than Microsoft Windows for hardware usability!

But this was not to be. It uses a vp7045 chipset, which has drivers both in Ubuntu 6.06 “Dapper” and in the latest v4l-dvb hg tree.

But for the life of me I couldn’t get it to tune into any TV stations (for those of you who like using hardware and not just having expensive boxes around, you will appreciate how tuning into a TV station is rather important functionality for a TV card). So I started having a look around the interweb for possible answers.

The best I could come up with was “are you sure you have all the cables plugged in” – yes, I was.

So seeing as this is the first digital TV dongle in this house, I wondered if the signal just wasn’t getting here. I got a friend to bring around a spare digital set top box. It worked fine. Brilliantly in fact – it even worked with the shitty small antenna that came with the dongle. So it wasn’t an ability to receive.

I then came across this post to the linux-dvb list titled “New VP7045 with TDA10046 instead of MT352 (was: VP7045 tuner doesn’t work)”. Which really does hint at the problem!

I could be one of the lucky ones with a new revision that uses the TDA10046 instead of the MT352! (after getting some debug info from the card out of the driver – it was reporting itself as v1.02, so quite possible).

Maybe time to hack the dvb driver for it? Things seem pretty modular, so it couldn’t be too hard, right?

Well, the vp7045-fe.c file is the front end (well, what it assumes is the front end) for the vp7045.c dongle. So all I really need to do is to get it to use the tda10046 frontend (under frontends/tda1004x.c) instead of the vp7045-fe.c fe code.

Well, it seems as though the tda10046 is an i2c device while the vp7045-fe isn’t. Hrrm… I’ve never really done much with i2c, so this’ll be fun!

I’ve currently managed to hack the driver so that we do some things to do with the tda chip – although i haven’t gotten in detecting the i2c adapter – which means we’re never going to get a front end! (in fact, when you plug in the device with my modified driver you get a “no frontend detected” message from the kernel).

i’ve tried poking on the #linuxtv channel on freenode to no avail – so it seems like i’m on my own for a bit.

A good way to spend midnight until 3am though :)

I’ll probably end up doing the same tonight. Why? Because it’s just so much fun.

Oh, and if anybody has any pointers – it would be appreciated.

I am, of course, assuming the hardware itself isn’t faulty. I have no MS Windows system around to test on.