From patchwork Fri Jan 15 09:06:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marius Vlad X-Patchwork-Id: 8039301 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 23712BEEE5 for ; Fri, 15 Jan 2016 09:05:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3950F20454 for ; Fri, 15 Jan 2016 09:05:35 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 4F6CE20453 for ; Fri, 15 Jan 2016 09:05:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C145C4A034; Fri, 15 Jan 2016 01:05:33 -0800 (PST) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTP id 4D424A56E for ; Fri, 15 Jan 2016 01:05:31 -0800 (PST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP; 15 Jan 2016 01:05:31 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,298,1449561600"; d="scan'208";a="891013000" Received: from mcvlad-wk.rb.intel.com ([10.237.105.57]) by orsmga002.jf.intel.com with ESMTP; 15 Jan 2016 01:05:30 -0800 From: Marius Vlad To: intel-gfx@lists.freedesktop.org Date: Fri, 15 Jan 2016 11:06:42 +0200 Message-Id: <1452848802-8041-2-git-send-email-marius.c.vlad@intel.com> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1452848802-8041-1-git-send-email-marius.c.vlad@intel.com> References: <1452848802-8041-1-git-send-email-marius.c.vlad@intel.com> Subject: [Intel-gfx] [PATCH i-g-t 2/2] lib/igt_kms: Short description between Intel/DRM terminology. X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP lib/igt_kms: Briefly describe Intel-to-DRM mapping between pipes, encoders and connectors. Signed-off-by: Marius Vlad --- lib/igt_kms.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) diff --git a/lib/igt_kms.c b/lib/igt_kms.c index c7a0b77..caa8837 100644 --- a/lib/igt_kms.c +++ b/lib/igt_kms.c @@ -68,6 +68,88 @@ * functions have all igt_ prefixes. This part is still very much work in * progress and so also lacks a bit documentation for the individual functions. * + * Intel/DRM terminology and display connections: + * + * Intel documentation describes the road from memory to an output connector as + * follows: + * + * |[!<-- language="C" --> + * .--------. .-------. .-------------. .-----. + * | Memory |---->| Pipes |---->| Transcoders |---->| DDI | + * '--------' '-------' '-------------' '-----' + * ]| + * + * Pipes represent the front-end of the display contain the planes, blending, + * and color correction, while the transcoders contain timing generators, + * encoders, A/V mixers and PSR (Panel-Self Refresh) controllers. Finally the + * DDI represent the connectors attached to the display. + * + * + * In DRM we have the following: + * + * |[!<-- language="C" --> + * .-----------. .-------. .-----------. .------------. + * | Framebuff |---->| Pipes |---->| Encoders |---->| Connectors | + * '-----------' '-------' '-----------' '------------' + * ]| + * + * + * The frame buffer ties a reference to a memory object and provides a pointer + * to the actual data. + * + * The pipe is used to set the display mode, timings and gamma tables. On some + * hardware models this is tied with the transcoder. In DRM-parlance this is + * referred as a CRTC. + * + * Each pipe has multiple planes. On older hardware these planes where known as + * primary plane, overlay/sprite plane, and cursor plane. From GEN9 (SKL/BXT) + * each pipe has three planes and a cursor plane. Each plane can be used as a + * primary, as a sprite or as an overlay plane. The planes are the ones that + * retrieve the pixels from memory and pushes them to the encoder. + * + * A pipe prior to GEN9: + * + * |[!<-- language="C" --> + * .--------. + * | Memory | .--------. + * | |------------>| Cursor |------>... + * | | '--------' + * | | + * | | .--------. + * | |-------->| Sprite |---------->... + * | | '--------' + * | | + * | | .---------. + * | |----->| Primary |------------>... + * | | '---------' + * '--------' + * ]| + * + * A pipe with universal planes: + * + * |[!<-- language="C" --> + * .--------. + * | Memory | .--------. + * | |------------>| Cursor |------>... + * | | '--------' + * | | + * | | .-------. + * | |-------->| Plane |---------->... + * | | '-------' + * | | + * | | .-------. + * | |----->| Plane |------------>... + * | | '-------' + * '--------' + * ]| + * + * The encoder is used to convert, depending on the output, pixels from pipes + * to signals understood by the connector. + * + * The connector will connect to the output display. This contains information + * about the attached display such as EDID, DPMS and information about modes + * supported by the display. + * * Note that this library's header pulls in the [i-g-t * framebuffer](intel-gpu-tools-Framebuffer.html) library as a * dependency.