Christophe Thommeret wrote: > 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. > > Correct, frontend1, demux1, dvr1 etc. All on the same adapter. The driver and multi-frontend patches manage exclusive access to the single internal resource. - Steve _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
