--- On Thu, 9/11/08, Steven Toth <stoth@xxxxxxxxxxx> wrote: > From: Steven Toth <stoth@xxxxxxxxxxx> > Subject: Re: DVB-S2 / Multiproto and future modulation support > To: "Christophe Thommeret" <hftom@xxxxxxx> > Cc: linux-dvb@xxxxxxxxxxx > Date: Thursday, September 11, 2008, 4:00 AM > 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 I wrote about it in a previous post, it's not always so. What about diversity (two frontends, single demux (or non if it's not TS based content)? _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
