From patchwork Tue Oct 24 01:08:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imre Deak X-Patchwork-Id: 13433811 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 CF398C00A8F for ; Tue, 24 Oct 2023 01:09:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BF06710E2AA; Tue, 24 Oct 2023 01:09:03 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id F351C10E29A; Tue, 24 Oct 2023 01:09:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698109741; x=1729645741; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Os9vjAs3NAshuBAE/Iluuvbe4iXWPuh64EHUG2H99Vs=; b=D6Lq4jB2tVLTQnpAERUJj4o2uzmuA9cJsltZlDsbSLSXC88FO2GZVmmy yascoyDn6PwNbq1kcP2r3+J6vR1GoXJ7RAmrEuWG/ZcRRTjSd5JnDFqE1 XOxvbbHgslYxvLRJqHohIj6+wGQgqPMjdRMlT39ITikFjP98IZ5k1Uvgo REUs16GjPt5RB1M7XGbMSQ4tm1EN/OwHqSXTQf9rt787yCr9BzjzIKODl TnvHeJuWgnsuoL0lqsuUhxh5RMynAEY1UqVpoFaeMxLx7PLfZXHPIzyRR R4r8haLJLeLcPypKyencuZ0n7R0lKG37PWiXixbdnHZ2bFi7HC4QtupnY g==; X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="366304329" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="366304329" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="931870006" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="931870006" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:00 -0700 From: Imre Deak To: intel-gfx@lists.freedesktop.org Subject: [PATCH 02/29] drm/dp_mst: Add helper to determine if an MST port is downstream of another port Date: Tue, 24 Oct 2023 04:08:58 +0300 Message-Id: <20231024010925.3949910-3-imre.deak@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231024010925.3949910-1-imre.deak@intel.com> References: <20231024010925.3949910-1-imre.deak@intel.com> 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: dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add drm_dp_mst_port_downstream_of_parent() required by the i915 driver in a follow-up patch to resolve a BW overallocation of MST streams going through a given MST port. Cc: Lyude Paul Cc: dri-devel@lists.freedesktop.org Reviewed-by: Lyude Paul Signed-off-by: Imre Deak --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 52 +++++++++++++++++++ include/drm/display/drm_dp_mst_helper.h | 3 ++ 2 files changed, 55 insertions(+) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 772b00ebd57bd..f733f620347f6 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -5126,6 +5126,58 @@ static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port, return false; } +static bool +drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + struct drm_dp_mst_port *parent) +{ + if (!mgr->mst_primary) + return false; + + port = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary, + port); + if (!port) + return false; + + if (!parent) + return true; + + parent = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary, + parent); + if (!parent) + return false; + + if (!parent->mstb) + return false; + + return drm_dp_mst_port_downstream_of_branch(port, parent->mstb); +} + +/** + * drm_dp_mst_port_downstream_of_parent - check if a port is downstream of a parent port + * @mgr: MST topology manager + * @port: the port being looked up + * @parent: the parent port + * + * The function returns %true if @port is downstream of @parent. If @parent is + * %NULL - denoting the root port - the function returns %true if @port is in + * @mgr's topology. + */ +bool +drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + struct drm_dp_mst_port *parent) +{ + bool ret; + + mutex_lock(&mgr->lock); + ret = drm_dp_mst_port_downstream_of_parent_locked(mgr, port, parent); + mutex_unlock(&mgr->lock); + + return ret; +} +EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent); + static int drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, struct drm_dp_mst_topology_state *state); diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h index 655862b3d2a49..e44485aa74e94 100644 --- a/include/drm/display/drm_dp_mst_helper.h +++ b/include/drm/display/drm_dp_mst_helper.h @@ -892,6 +892,9 @@ drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state, struct drm_dp_mst_atomic_payload * drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state, struct drm_dp_mst_port *port); +bool drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + struct drm_dp_mst_port *parent); int __must_check drm_dp_atomic_find_time_slots(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr, From patchwork Tue Oct 24 01:08:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imre Deak X-Patchwork-Id: 13433812 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 0A1BCC25B6B for ; Tue, 24 Oct 2023 01:09:13 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B02A210E2B0; Tue, 24 Oct 2023 01:09:09 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id A6FC310E2A1; Tue, 24 Oct 2023 01:09:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698109743; x=1729645743; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Bqn4DEX4WgPl/QDjc9Ss6gHfFic+mc3myfgfkAfUr+w=; b=fVUrEZBZngYpkbxVPBOfQj9ay9joe3iJZ9tTWlAsswVyHpNiIgvboEJ6 xiWkEhvn0HAvhhGxnSDY9RHJtEtxNkjGmJZ+V/9zH6poyGKkU6YIyd4Gs UtPVYsNWUmtQ25i8E3xhXovIFBPzodvbDgFskuFYPyKH0EYDhOAqMzNiZ G7+NPyRXENHPosgC3UcVp9XI7KVrR73mZ/TCdg8cGhgwHTM3yLOcpJ/Ca r4PQYTZyopeL3idzzxVKYYSMhlBrmtp/pHNWcmcG8peu9yBM/aavwc50f urZEtREUxJMWjLzbKRnisnwCWmaxn31DQ9F3pnzI9u1a2bXJjCg1ISDTd A==; X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="366304334" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="366304334" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="931870010" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="931870010" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:01 -0700 From: Imre Deak To: intel-gfx@lists.freedesktop.org Subject: [PATCH 03/29] drm/dp_mst: Factor out a helper to check the atomic state of a topology manager Date: Tue, 24 Oct 2023 04:08:59 +0300 Message-Id: <20231024010925.3949910-4-imre.deak@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231024010925.3949910-1-imre.deak@intel.com> References: <20231024010925.3949910-1-imre.deak@intel.com> 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: dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Factor out a helper to check the atomic state for one MST topology manager, returning the MST port where the BW limit check has failed. This will be used in a follow-up patch by the i915 driver to improve the BW sharing between MST streams. Cc: Lyude Paul Cc: dri-devel@lists.freedesktop.org Reviewed-by: Lyude Paul Signed-off-by: Imre Deak --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 93 +++++++++++++++---- include/drm/display/drm_dp_mst_helper.h | 4 + 2 files changed, 78 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index f733f620347f6..a86a67d3516ff 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -5180,11 +5180,13 @@ EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent); static int drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, - struct drm_dp_mst_topology_state *state); + struct drm_dp_mst_topology_state *state, + struct drm_dp_mst_port **failing_port); static int drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb, - struct drm_dp_mst_topology_state *state) + struct drm_dp_mst_topology_state *state, + struct drm_dp_mst_port **failing_port) { struct drm_dp_mst_atomic_payload *payload; struct drm_dp_mst_port *port; @@ -5213,7 +5215,7 @@ drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb, drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb); list_for_each_entry(port, &mstb->ports, next) { - ret = drm_dp_mst_atomic_check_port_bw_limit(port, state); + ret = drm_dp_mst_atomic_check_port_bw_limit(port, state, failing_port); if (ret < 0) return ret; @@ -5225,7 +5227,8 @@ drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb, static int drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, - struct drm_dp_mst_topology_state *state) + struct drm_dp_mst_topology_state *state, + struct drm_dp_mst_port **failing_port) { struct drm_dp_mst_atomic_payload *payload; int pbn_used = 0; @@ -5246,13 +5249,15 @@ drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] no BW available for the port\n", port->parent, port); + *failing_port = port; return -EINVAL; } pbn_used = payload->pbn; } else { pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb, - state); + state, + failing_port); if (pbn_used <= 0) return pbn_used; } @@ -5261,6 +5266,7 @@ drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n", port->parent, port, pbn_used, port->full_pbn); + *failing_port = port; return -ENOSPC; } @@ -5438,20 +5444,79 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state, } EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc); +/** + * drm_dp_mst_atomic_check_mgr - Check the atomic state of an MST topology manager + * @state: The global atomic state + * @mgr: Manager to check + * @mst_state: The MST atomic state for @mgr + * @failing_port: Returns the port with a BW limitation + * + * Checks the given MST manager's topology state for an atomic update to ensure + * that it's valid. This includes checking whether there's enough bandwidth to + * support the new timeslot allocations in the atomic update. + * + * Any atomic drivers supporting DP MST must make sure to call this or + * the drm_dp_mst_atomic_check() function after checking the rest of their state + * in their &drm_mode_config_funcs.atomic_check() callback. + * + * See also: + * drm_dp_mst_atomic_check() + * drm_dp_atomic_find_time_slots() + * drm_dp_atomic_release_time_slots() + * + * Returns: + * - 0 if the new state is valid + * - %-ENOSPC, if the new state is invalid, because of BW limitation + * @failing_port is set to: + * - The non-root port where a BW limit check failed + * The returned port pointer is valid until at least + * one payload downstream of it exists. + * - %NULL if the BW limit check failed at the root port + * - %-EINVAL, if the new state is invalid, because the root port has + * too many payloads. + */ +int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state, + struct drm_dp_mst_port **failing_port) +{ + int ret; + + *failing_port = NULL; + + if (!mgr->mst_state) + return 0; + + ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state); + if (ret) + return ret; + + mutex_lock(&mgr->lock); + ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary, + mst_state, + failing_port); + mutex_unlock(&mgr->lock); + + return ret < 0 ? ret : 0; +} +EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr); + /** * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an * atomic update is valid * @state: Pointer to the new &struct drm_dp_mst_topology_state * * Checks the given topology state for an atomic update to ensure that it's - * valid. This includes checking whether there's enough bandwidth to support - * the new timeslot allocations in the atomic update. + * valid, calling drm_dp_mst_atomic_check_mgr() for all MST manager in the + * atomic state. This includes checking whether there's enough bandwidth to + * support the new timeslot allocations in the atomic update. * * Any atomic drivers supporting DP MST must make sure to call this after * checking the rest of their state in their * &drm_mode_config_funcs.atomic_check() callback. * * See also: + * drm_dp_mst_atomic_check_mgr() * drm_dp_atomic_find_time_slots() * drm_dp_atomic_release_time_slots() * @@ -5466,21 +5531,11 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state) int i, ret = 0; for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) { - if (!mgr->mst_state) - continue; + struct drm_dp_mst_port *tmp_port; - ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state); + ret = drm_dp_mst_atomic_check_mgr(state, mgr, mst_state, &tmp_port); if (ret) break; - - mutex_lock(&mgr->lock); - ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary, - mst_state); - mutex_unlock(&mgr->lock); - if (ret < 0) - break; - else - ret = 0; } return ret; diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h index e44485aa74e94..a4aad6df71f18 100644 --- a/include/drm/display/drm_dp_mst_helper.h +++ b/include/drm/display/drm_dp_mst_helper.h @@ -916,6 +916,10 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr, int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, struct drm_dp_query_stream_enc_status_ack_reply *status); +int __must_check drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state, + struct drm_dp_mst_port **failing_port); int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state); int __must_check drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state, struct drm_dp_mst_topology_mgr *mgr); From patchwork Tue Oct 24 01:09:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imre Deak X-Patchwork-Id: 13433813 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 A88F3C00A8F for ; Tue, 24 Oct 2023 01:09:15 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4298D10E2B1; Tue, 24 Oct 2023 01:09:11 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3EF1010E2A1; Tue, 24 Oct 2023 01:09:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698109745; x=1729645745; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=VsqM1xF/AplsEwiGjrP6+aBGayu1M/I9KPvAI2Cpm6U=; b=lJkfAYjzv8zkoTN2yYR7rjNE1MAbVhn3MXeDEJcqz9+1XGPl4YojtbSx m2ZOcUQwDv81djooSPQ1kEDNDyEk6Q7qmKokQ2OZGRpD0tRNXP6saLU0H dh5zCM9u+/+n94D1d5B74IUj9dYG7NVMDFez3ZTI0dsPh0wyLpuGlclUl cRWGtQvRHxLDXc8MakHt6Gf4HNwwHDb6GO36CKKIcAJ9enPTazgKNs2Ie jk5SK3ioo8IFboGUwF18l/hUXixsM8VaysZB52uXffWdK14I4UyLIVRDs oPwGkvaIjlagVhlVfRRiTjl2uQywwxkDcVknaCudFwIf3SrFqiwrXapRF Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="366304338" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="366304338" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10872"; a="931870012" X-IronPort-AV: E=Sophos;i="6.03,246,1694761200"; d="scan'208";a="931870012" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 18:09:03 -0700 From: Imre Deak To: intel-gfx@lists.freedesktop.org Subject: [PATCH 04/29] drm/dp_mst: Swap the order of checking root vs. non-root port BW limitations Date: Tue, 24 Oct 2023 04:09:00 +0300 Message-Id: <20231024010925.3949910-5-imre.deak@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231024010925.3949910-1-imre.deak@intel.com> References: <20231024010925.3949910-1-imre.deak@intel.com> 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: dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" drm_dp_mst_atomic_check_mgr() should check for BW limitation starting from sink ports continuing towards the root port, so that drivers can use the @failing_port returned to resolve a BW overallocation in an ideal way. For instance from streams A,B,C in a topology A,B going through @failing_port and C not going through it, a BW overallocation of A,B due to a limit of the port must be resolved first before considering the limits of other ports closer to the root port. This way can avoid reducing the BW of stream C unnecessarily due to a BW limit closer to the root port. Based on the above swap the order of the BW check for the root port and the check for all the ports downstream of it (the latter going through the topology already in the sink->root port direction). Cc: Lyude Paul Cc: dri-devel@lists.freedesktop.org Reviewed-by: Lyude Paul Signed-off-by: Imre Deak --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index a86a67d3516ff..5972c93615f18 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -5469,9 +5469,13 @@ EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc); * - %-ENOSPC, if the new state is invalid, because of BW limitation * @failing_port is set to: * - The non-root port where a BW limit check failed + * with all the ports downstream of @failing_port passing + * the BW limit check. * The returned port pointer is valid until at least * one payload downstream of it exists. * - %NULL if the BW limit check failed at the root port + * with all the ports downstream of the root port passing + * the BW limit check. * - %-EINVAL, if the new state is invalid, because the root port has * too many payloads. */ @@ -5487,17 +5491,16 @@ int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state, if (!mgr->mst_state) return 0; - ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state); - if (ret) - return ret; - mutex_lock(&mgr->lock); ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary, mst_state, failing_port); mutex_unlock(&mgr->lock); - return ret < 0 ? ret : 0; + if (ret < 0) + return ret; + + return drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state); } EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr);