Em Fri, 9 Jul 2021 23:47:39 +0800 YP WU <yp.wu@xxxxxxxxxxxx> escreveu: > >From: YP WU <yp.wu@xxxxxxxxxxxx> > >>To: <mchehab@xxxxxxxxxx> > >>Cc: <Jason-BF.Huang@xxxxxxxxxxxx>, <Lecopzer.Chen@xxxxxxxxxxxx>, > >> <francis.lee@xxxxxxxxxxxx>, <gustavoars@xxxxxxxxxx>, > >> <hverkuil-cisco@xxxxxxxxx>, <leo.hsiao@xxxxxxxxxxxx>, > >> <linux-kernel@xxxxxxxxxxxxxxx>, <linux-media@xxxxxxxxxxxxxxx>, > >> <yp.wu@xxxxxxxxxxxx> > >>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@xxxxxxxxxxxx> (raw) > >>In-Reply-To: <20210623093312.6f9883a5@xxxxxxxx> > >> > >>Hello, Mr.Mauro, > >><I need to understand more about the use case. > >>-> 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
