Le Thursday 11 September 2008 00:59:31 Andreas Oberritter, vous avez écrit : > Hans Werner wrote: > >> So applications could know that these 2 frontends are exclusive. > >> That would not require any API change, but would have to be a rule > >> followed by > >> all drivers. > > > > Yes, if we keep to that rule then only frontends which can operate truly > > simultaneously should have a different adapter number. > > An adapter refers to a self-contained piece of hardware, whose parts can > not be used by a second adapter (e.g. adapter0/demux0 can not access the > data from adapter1/frontend1). In a commonly used setup it means that > adapter0 is the first initialized PCI card and adapter1 is the second. > > Now, if you want a device with two tuners that can be accessed > simultaneously to create a second adapter, then you would have to > artificially divide its components so that it looks like two independant > PCI cards. This might become very complicated and limits the functions > of the hardware. > > However, on a setup with multiple accessible tuners you can expect at > least the same amount of accessible demux devices on the same adapter > (and also dvr devices for that matter). There is an ioctl to connect a > frontend to a specific demux (DMX_SET_SOURCE). > > So, if there are demux0, frontend0 and frontend1, then the application > knows that it can't use both frontends simultaneously. Otherwise, if > there are demux0, demux1, frontend0 and frontend1, then it can use both > of them (by using both demux devices and connecting them to the > frontends via the ioctl mentioned above). Sounds logical. And that's why Kaffeine search for frontend/demux/dvr > 0 and uses demux1 with frontend1. (That was just a guess since i've never seen neither any such devices nor comments/recommendations/rules about such case). However, all dual tuners devices drivers i know expose the 2 frontends as frontend0 in separate adapters. But all these devices seems to be USB. The fact that Kaffeine works with the experimental hvr4000 driver indicates that this driver populates frontend1/demux1/dvr1 and then doesn't follow the way you describe (since the tuners can't be used at once). I would like to hear from Steve on this point. -- Christophe Thommeret _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
