[vdr] Multiple frontends on a single PCI card

Steven Toth stoth at hauppauge.com
Mon Oct 9 17:44:09 CEST 2006


Some background:

I'm working on patches to add support for multiple frontends on a single 
adapter, in effect /dev/dvb/adapter0/fe{0,1,...} etc. A single transport 
bus service different types of demodulators.

I've also been working on patches to add support for the WinTV-HVR1300 
(single transport bus shared between a DVB-T demod and a cx23416 MPEG2 
hardware encoder).

Both sets of patches help resolve problems where two process open two 
different devices which share common hardware, and subsequently break 
each others streaming session.

In order to guarantee that the hardware resources are allocated 
correctly (cx88 driver) and do not get reprogrammed on the fly by a 
separate process, the frontends now request hardware access and could 
cause open to fail on the frontend with -EBUSY.

Now that the background is out of the way, how will VDR deal with a 
simple single PCI board with this configuration?
/dev/dvb/adapter0/fe0 (dvb-t demod)
/dev/dvb/adapter0/fe1 (dvb-s demod)
<other regular dvb files here>

... where attempts to open multiple frontends will result in one of the 
open calls resulting in -EBUSY.

... or won't it?

If it doesn't work, how would you like this to be implemented in the 
drivers, so that a better VDR solution can be built?



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