I'm trying to get a DVB-T (digital terrestrial television) key working. There isn't much non-techie-oriented information around about DVB in Linux yet, which doesn't help. So perhaps an expert can help with this thread..?

I'm using a very recent kernel (2.6.12.3), so I believe the basic modules for DVB are all there. And since free DVB-T broadcasts are simply encoded in MPEG2, this problem can't be too difficult to solve.

Questions:

1. A full range of adapters and devices appears under /dev/dvb in my device tree. Does this mean that DVB is indeed enabled in the kernel and that I don't need to go recompiling that?

2. The devices under each of the adapters (audio0, ca0, demux0, dvr0, frontend0, net0, osd0, video) seem to be indicated as inactive, or unplugged (yellow text on black in xterm). What does this indicate for a device?

3. What is the basic method for accessing a "transport stream" thru USB? If this was a storage device I would just mount it, and presto. But it isn't. Also, dmesg acknowledges plugging-in of the key but doesn't provide any product details. Is this significant?

As you can see, I'm only at first base here. All pointers really appreciated.

Sorry, never heard a DVB-usb-key for this purpose.
May be it is a usb-card ?
Go here http://www.linuxtv.org/downloads/dvb/
and download
linuxtv-dvb-apps-1.1.0.tar.bz2
compile it (it is not necessary you install the tools)
and try to get a suitable channels.conf according to instructions.
If your hardware is supported (BTW what card is yours?) you'll be able to watch TV on your Linux box.
Anyway, since you asked for defined responses.....

1) Basically yes, may be the frontend module is missing (on my system dvd-core and skystar modules are loaded correctly, but the frontend module, mine is mt312, for some reason is not).

2) Device nodes (files) are usually created by a script managed by udev in recent kernels. If you find such nodes in your /dev directory it just means something created them, they cannot defined active or inactive since they are used mostly as a "buffer" or sometimes similarely as a "socket". In other words if they exist it does not means your hardware (which they are related) is working properly.

3) MPEG stream is manged by the driver(s) and codec(s). If the driver has been designed for the usb bus it can manage the stream simalarely to PCI bus. Is a matter of designing the driver.

Hope this helps
Ciao

Thanks for that, urka, I appreciate you taking the time to help.

I've definitely done this the hard way. The thing is indeed a key, or maybe it's a stick. Very small anyway. Unknown Chinese brand Intuix and no indication of what chipset it is based on, though lsusb indicates the vendor Lite-On Technology.

I've found some likely-looking firmware files to drop into the hotplug firmware directory, but these require a couple of device drivers (dvb-usb, most importantly) which are not in my tree under /lib/modules/$kernel/. It seems that things are moving so quickly in the world of DVB that my 2.6.12.3 kernel is already obsolete and I need to upgrade to get all the new modules. Guess it's all part of the fun.

Another entire day spent on this one, still can't get the hardware working.

I compiled a brand new 2.6.13.4 kernel, which contains all the main DVB drivers including the important USB one, dvb-usb.ko. The '/dev/dvb' nodes are all in place. Hotplug is working, and all the possible firmware drivers (I can't be sure which is the correct one) are sitting in '/usr/lib/hotplug/firmware', where they are supposed to be picked up on insertion of the hardware.

But this is all I get when the hardware is inserted:

Output of 'lsusb' reveals a bit more:

As I understand it (and it took time!) an application called 'udev' looks at the contents of /sys and assigns USB devices to nodes according to the data in '/lib/modules/$kernel/modules.usbmap'. This is a table created by 'depmod' which references USB device numbers against their corresponding kernel modules.

So!.. A couple of questions for any generous, bright person who knows something about all this and would like to help me out of my misery...

1. The 'modules.usbmap' table does not contain a reference to the device number of my USB device. Does that mean that no kernel module contains such a reference? Would it be dangerously cheeky to insert one, along the lines of a very similar device?

2a. How can I be sure that hotplug really is checking '/usr/lib/hotplug/firmware' when it detects the new device? The standard advice is to look for '/etc/hotplug/firmware.agent', which is there. But 'hotplug --help' produces no output.

2b.Might the following kernel config changes make any difference with hotplug?

Lots of detail there, hope it's not too much. Would so appreciate some pointers on this one...

Thanks.

Hey, did you get an answer?

Have you managed to get this to work yet? If you did how?

Thanks

Michael

Nope, still waiting for inspiration here. But now there's two of us, maybe some DVB uber-expert will notice! What are you trying to get working?

Picture of device in question at http://www.liteon.com/prod/getProduc...menu_id=4_2_22

If no-one can help here, we could try the Linux DVB mailing list at linux-tv.org. The latest monthly digest of that is at http://www.linuxtv.org/pipermail/lin...October.txt.gz

Still, it would be good to make some progress on the record at LinuxQuestions.

Anyone?

I'm trying to get a videa dvt-100 working, see http://www.videa-tech.com.tw/dtv_100.asp

I haven't made any real progress. I'm trying to get this work for my degree and all I really need is some pointers of how to get this thing started so I can write the driver myself. I've intercepted the communications between the device and the driver but now I need to know how to take the data I got and turn that into a driver. If anyone wants to point me in the right direction I would be most greatfull.