From patchwork Wed Jul 27 10:36:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 594250 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94936C04A68 for ; Wed, 27 Jul 2022 10:37:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231355AbiG0KhB (ORCPT ); Wed, 27 Jul 2022 06:37:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiG0KhA (ORCPT ); Wed, 27 Jul 2022 06:37:00 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA78246D9E for ; Wed, 27 Jul 2022 03:36:59 -0700 (PDT) Received: from deskari.lan (91-158-154-79.elisa-laajakaista.fi [91.158.154.79]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 1B0FDA49; Wed, 27 Jul 2022 12:36:57 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1658918217; bh=GqmAEUVbADTeNJfLyMDV3V2m2+B8HbVTtNvKPR/DViU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kPNIlzVkU3Ge2Sl22NkHvNarGsGwJcyt8gNxgs+MkpLUAJmTRlD554LMKdSDRbGLZ YyzcTron/b5PRWmPVDnXoHe9WsIEFlW4HNakjIlMqy7s2VL1Zwf4lE5imWNPsAddYX e2ZGTBBH6S79ByNrtm5nW5OaSOPAMtGZoSI/mZFs= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav , Kishon Vijay Abraham , satish.nagireddy@getcruise.com, Tomasz Figa Cc: Tomi Valkeinen Subject: [PATCH v12 01/30] media: Documentation: mc: add definitions for stream and pipeline Date: Wed, 27 Jul 2022 13:36:10 +0300 Message-Id: <20220727103639.581567-2-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220727103639.581567-1-tomi.valkeinen@ideasonboard.com> References: <20220727103639.581567-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The doc talks about streams and pipelines, but doesn't really define them. This is an attempt to define them according to my understanding. Signed-off-by: Tomi Valkeinen --- Documentation/driver-api/media/mc-core.rst | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst index 02481a2513b9..2a0c0aeec5f2 100644 --- a/Documentation/driver-api/media/mc-core.rst +++ b/Documentation/driver-api/media/mc-core.rst @@ -213,6 +213,18 @@ Link properties can be modified at runtime by calling Pipelines and media streams ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +A media stream is a stream of pixels or metadata originating from one or more +source devices (such as a sensors) and flowing through media entity pads +towards the final sinks. The stream can be modified on the route by the +devices (e.g. scaling or pixel format conversions), or it can be split into +multiple branches, or multiple branches can be merged. + +A media pipeline is a set of media streams which are interdependent. This +interdependency can be caused by the hardware (e.g. configuration of a second +stream cannot be changed if the first stream has been enabled) or by the driver +due to the software design. Most commonly a media pipeline consists of a single +stream which does not branch. + When starting streaming, drivers must notify all entities in the pipeline to prevent link states from being modified during streaming by calling :c:func:`media_pipeline_start()`.