From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from hqemgate16.nvidia.com ([216.228.121.65]:8281 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754562AbbIXR0i (ORCPT ); Thu, 24 Sep 2015 13:26:38 -0400 Subject: Re: [Question]: What's right way to use struct media_pipeline? To: Hans Verkuil , References: <56035829.2080300@nvidia.com> <5603B8B3.3060109@xs4all.nl> CC: From: Bryan Wu Message-ID: <5604324D.70000@nvidia.com> Date: Thu, 24 Sep 2015 10:26:37 -0700 MIME-Version: 1.0 In-Reply-To: <5603B8B3.3060109@xs4all.nl> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 09/24/2015 01:47 AM, Hans Verkuil wrote: > On 09/24/2015 02:55 AM, Bryan Wu wrote: >> Hi Hans, >> >> I found struct media_pipeline actually is completely empty and I assume we use that to control all the entities belonging to one media_pipeline. >> >> media_pipeline should contains either all the media_link or all the media_entity. How come an empty struct can provide those information? > It's basically an empty base class to speak in C++ terminology. > > See drivers/media/platform/xilinx/xilinx-dma.h on how it is used there. > > Laurent Pinchart knows a lot more about it than I do, though. > Hi Laurent, I have a subdev media entity which have 4 media pads. pad[0] is sink and pad[1] is source, these 2 pads belong to the first media pipeline pad[2] is sink and pad[3] is source, these 2 pads belong to the second media pipeline Actually our hardware Tegra has 3 these kind of entities, so totally we have 6 media pipelines like 6 dma channels. How to handle that with media pipeline framework? I saw in xilinx driver it just has one pipeline which is shared by several DMA channels, right? -Bryan > >> What about following ideas? >> 1. when media_entity_create_links, it will return a media_link pointer. >> 2. we save this media_link pointer into the media_pipeline >> 3. use this media_pipeline for start streaming, stop streaming and validate links. >> >> Maybe I miss something during recent media controller changes. >> >> Thanks, >> -Bryan >> >> ----------------------------------------------------------------------------------- >> This email message is for the sole use of the intended recipient(s) and may contain >> confidential information. Any unauthorized review, use, disclosure or distribution >> is prohibited. If you are not the intended recipient, please contact the sender by >> reply email and destroy all copies of the original message. >> -----------------------------------------------------------------------------------