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=-8.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 7E41FC07E96 for ; Thu, 15 Jul 2021 07:59:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F5CB608FC for ; Thu, 15 Jul 2021 07:59:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232111AbhGOICe (ORCPT ); Thu, 15 Jul 2021 04:02:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:40044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230076AbhGOICc (ORCPT ); Thu, 15 Jul 2021 04:02:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E6ABE60FF1; Thu, 15 Jul 2021 07:59:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626335979; bh=F2d6pZDd/k4RQziKFXVrRyT3ygLkgNvuOwnd7LZQ97Y=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qbeMC2ldZNTuY7ea55yX6ICVCrfKrCSnkWKQWmoz/sT4hNY/clOzGxQgQUSlEsFku 5zKcCRAUIJWMzMO5ExQjfZ1L5Hog/8lyLrGyjYU6Y0zEY3mJ13pLBVj/aR1IKr1zIR H1Fllu/ee1MQHTXNkrOgixMBlyzGnKDDtVTILH2rg7HG3t489wCqD3sctYVFvyQSCv OBfcI7g36X1MfAFuhBbq7i13gAhGcyr09fv7KC9ju4g0+duNJ4ecbZyCnvOJ+KxvdY hMgtAVIz+VG66CHnaD3FVaHJUAFdP31QiBruouAahdvkVnrSE1sCS+mrciF9pZAEs7 wmVl1msBublaA== Date: Thu, 15 Jul 2021 09:59:33 +0200 From: Mauro Carvalho Chehab To: YP WU Cc: , , , , , , , Subject: Re: How to use "DTV_FE_CAPABILITY" command for Frontend.h of Linux DVB Message-ID: <20210715095933.63dbcd31@coco.lan> In-Reply-To: <20210709154739.30394-1-yp.wu@mediatek.com> References: <20210623093312.6f9883a5@coco.lan> <20210709154739.30394-1-yp.wu@mediatek.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Em Fri, 9 Jul 2021 23:47:39 +0800 YP WU escreveu: > >From: YP WU > >>To: > >>Cc: , , > >> , , > >> , , > >> , , > >> > >>Subject: Re: How to use "DTV_FE_CAPABILITY" command for Frontend.h of Linux DVB > >>Date: Fri, 2 Jul 2021 17:28:34 +0800 > >>Message-ID: <20210702092834.11699-1-yp.wu@mediatek.com> (raw) > >>In-Reply-To: <20210623093312.6f9883a5@coco.lan> > >> > >>Hello, Mr.Mauro, > >> >>-> About use case, I describe below: > >> > >> For our design of kernel, demod/tuner and LNB are registered to different frontend device nodes. > >>We want to implement property command to know if the frontend device node is LNB device or demod/tuner device. > >>If it is LNB device node, the value would return true > >>If it is demod/tuner device node, the value would return false. > >> > >>Do you have better idea or suggestion for our usage? > >>Please let me know if your have better suggestion. > >>Very thank you for your help. > >> > >>BRs, > >>YP > > Hello, Mr.Mauro, > Frist of all, thanks for your reply. > Based on previous discussion, we think we can create a new property command to achieve our goal. > A new property command "DTV_FE_LNB_CAPABILITY". > We can use "FE_GET_PROPERTY" with case "DTV_FE_LNB_CAPABILITY" to get LNB capability. > We also should add a new variable named "LNB_capability" in dtv_frontend_properties. Like below: > bool LNB_capability; > If the device node is LNB, LNB_capability should set to TRUE. > If the device node is demod/tuner, LNB_capability should set to FALSE. > > What's your opinion? > If you have a better idea or suggestion, please let me know. It sounds that there are some misunderstanding here, specially when you mention a "LNB device node". See this picture: https://linuxtv.org/downloads/v4l-dvb-apis-new/_images/typical_media_device.svg The way the DVB API maps the hardware is that the frontend groups: - tuner; - demod; - Satellite Equipment Control (SEC). While not explicitly there, LNB is part of the frontend (it is part of the SEC, for satellite systems like DVB-S/S2). some tuners may also have LNBs before them. So, there's no separate device node for it. Everything is controlled via the /dev/dvb/frontend* device nodes. So, it is not clear yet why are you considering to have a separate devnode for the LNB. Thanks, Mauro