From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C609C43387 for ; Wed, 19 Dec 2018 12:20:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A873217D6 for ; Wed, 19 Dec 2018 12:20:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728799AbeLSMUN (ORCPT ); Wed, 19 Dec 2018 07:20:13 -0500 Received: from quechua.inka.de ([193.197.184.2]:51176 "EHLO mail.inka.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727993AbeLSMUN (ORCPT ); Wed, 19 Dec 2018 07:20:13 -0500 Received: from localhost by mail.inka.de with local-rmail id 1gZapg-0003tF-4I; Wed, 19 Dec 2018 13:20:12 +0100 Received: by raven.inka.de (Postfix, from userid 1000) id CCD1A120201; Wed, 19 Dec 2018 13:16:49 +0100 (CET) Date: Wed, 19 Dec 2018 13:16:49 +0100 From: Josef Wolf To: linux-media@vger.kernel.org Subject: Re: SYS_DVBS vs. SYS_DVBS2 Message-ID: <20181219121649.GK11337@raven.inka.de> Mail-Followup-To: Josef Wolf , linux-media@vger.kernel.org References: <20181219102846.GJ11337@raven.inka.de> <20181219092211.16d67c61@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181219092211.16d67c61@coco.lan> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 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@raven.inka.de