From patchwork Mon Oct 23 20:36:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Ser X-Patchwork-Id: 13433535 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2A5CEC25B46 for ; Mon, 23 Oct 2023 20:37:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3327110E251; Mon, 23 Oct 2023 20:37:13 +0000 (UTC) Received: from mail-4323.proton.ch (mail-4323.proton.ch [185.70.43.23]) by gabe.freedesktop.org (Postfix) with ESMTPS id A47DD10E251 for ; Mon, 23 Oct 2023 20:37:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=emersion.fr; s=protonmail2; t=1698093428; x=1698352628; bh=6R+cYz/+24V5uIpS0LWCGlyrH2ctZC35+YakAciBjaA=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=dZQ9a4Ya/0cxfIE23chpRkZH4CUAbE1EKOoyajuQr5z6iJNK5S4lPaEjzQvZv9txk AKgbG2vY7qzXEfSeT08+papynAS8rR4nPTeBVA3qicLxq4FnIiXsEMp0BTV4YFqjh2 c8YeBRDsnzpqDxnlHD8ffZ5n1wG8JZOa+AFCma2z6fE76e4WRfSAGq5VZqxhomuf60 RRnjKwRjlFqHUDTC1FR8HWevLnniQoAryFT87iXltee76LkL96bfwHof74rfzATeDt dx8kJaBjegU28jHeZ6lwoB5KvW3VnABiVIkD+jSzbgxb2wMl3GWvGmpO/8SKNKu2Ft 2yJrSWVamNoDA== Date: Mon, 23 Oct 2023 20:36:39 +0000 To: dri-devel@lists.freedesktop.org From: Simon Ser Subject: [PATCH] drm/doc: describe PATH format for DP MST Message-ID: <20231023203629.198109-1-contact@emersion.fr> Feedback-ID: 1358184:user:proton MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dmitry Baryshkov , Daniel Vetter , Pekka Paalanen , wayland-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This is already uAPI, xserver parses it. It's useful to document since user-space might want to lookup the parent connector. Additionally, people (me included) have misunderstood the PATH property for being stable across reboots, but since a KMS object ID is baked in there that's not the case. So PATH shouldn't be used as-is in config files and such. Signed-off-by: Simon Ser Cc: Pekka Paalanen Cc: Dmitry Baryshkov Cc: Daniel Vetter Reviewed-by: Dmitry Baryshkov Acked-by: Pekka Paalanen --- drivers/gpu/drm/drm_connector.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index c3725086f413..392bec1355a3 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -1198,6 +1198,11 @@ static const u32 dp_colorspaces = * drm_connector_set_path_property(), in the case of DP MST with the * path property the MST manager created. Userspace cannot change this * property. + * + * In the case of DP MST, the property has the format + * ``mst:-`` where ```` is the KMS object ID of the + * parent connector and ```` is a hyphen-separated list of DP MST + * port numbers. Note, KMS object IDs are not stable across reboots. * TILE: * Connector tile group property to indicate how a set of DRM connector * compose together into one logical screen. This is used by both high-res