Am 15.11.2011 11:52, schrieb Steffen Barszus:
2011/11/15 Hawes, Mark<>:
What i got from previous discussions on linux-media is, that if the
device nodes are created within one adapter, an application needs to
assume that
the devices can not be used concurrently and needs to close
one "device node group" before opening the other one.

This suggests a constraint in the current design of the way VDR handles
the detection and use of DVB devices in that it cannot handle so called
'hybrid' cards where two (or more!) frontends are attached via a single
adaptor without restarting VDR and identifying which frontend to use.

As already mentioned I wish to use both cards on my system and I'd be
interested and happy to help in developing a patch to overcome this
constraint. However I would need some VDR architectural guidance to
suggest how this might be done with minimal disruption to the current
DVB device handling. Any direction would be much appreciated.

What i said above is AFAIK more or less undocumented up to now. But it
seems to be a consensus between most driver developers now.

Yes vdr needs to change to handle this devices properly based on the
previous assumptions, i think soneone else can be more helpful than me

I'm just preparing a test environment for extending the vdr to use multi-frontend devices. Good to know that there are drivers which behaves different in creating device nodes. The Cine-C/T cards for example creates only one demux/dvr node and two frontends. Soon I will have my hands on such a device. If I can get a patch working for this card it's only a small step to support the HVR 4000, two.

I have already dealt with vdr devices and have some knowledge about the concepts. I developed the dynamite plugin which extends vdr with some device hotplugging capabilities. It also requires patching the vdr. But with this you can use both devices without restarting vdr and affecting timers and recordings. But for now there's no automatism so that the right device for the watched/recorded channel is attached. Please have a look at the README if you're interested. If you have questions, just ask.

 If you want to develop something on your own, start reading device.[hc] and 
dvbdevice.[hc] at the vdr source.
I definitly will try to develop a "multi-frontend-patch" but spare time is always rare. I will reserve one evening per week for this. And I hope to finish it till christmas. ;-)

If you have ideas please let me know. I'm looking for some inspiration for storing the different frontend capabilities at the cDvbDevice and how to maintain the different cDvbTuner objects. My experience while working on dynamite will help me in particular since I invested some time on closing/reopening the file handles at the right places. Hotplugging "single frontend" devices seems to be a good first step towards the solution of this problem.


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