Thanks for your response, Mauro! On Wed, Dec 19, 2018 at 09:22:11AM -0200, Mauro Carvalho Chehab wrote: > Em Wed, 19 Dec 2018 11:28:46 +0100 > Josef Wolf <jw@xxxxxxxxxxxxx> escreveu: > > I would like to know how to know whether for a specific program SYS_DVBS or > > SYS_DVBS2 should be specified to the FE_SET_PROPERTY ioctl() call. > > This is not specific to a program. It affects the hole transponder. Either > the transponder is DVB-S or DVB-S2. Yes, I'm aware of it. In my question I meant: when I want to tune to some program, I need to set the SYS_DVBx property in addition to the other tuning parameters (like frequency, polarization, FEC etc/pp) > > Is this somehow broadcasted in some PAT/PMT tables? > > It is at the NAT tables. They contain all needed information to properly > tune into the transponders. There are different tables, depending if the > transponder is -S or -S2. OK. > > Or is it possible to simple always specify SYS_DVBS2 and the kernel will > > manage the backwards compatibilities when a DVB-S transponder is specified in > > the tuning parameters? > > The Kernel can't and shouldn't guess the tuning parameters. It depends > on userspace to parse the NAT tables and get it right. It is pretty much obvois to me that the kernel can't guess tuning parameters like diseqc-sequence, polarity, frequency and symrate. This is because the kernel needs those parameters to get a signal at all. But, on the other side, there are lots of parameters that the kernel (or hardware?) _can_ guess: INVERSION_AUTO, FEC_AUTO, QAM_AUTO just to name some. So what' so special about SYS_DVBS/SYS_DVBS2 that it has to be handled differently from those other parameters? -- Josef Wolf jw@xxxxxxxxxxxxx
