From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98FCBC43603 for ; Sat, 21 Dec 2019 00:11:57 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 67B3220866 for ; Sat, 21 Dec 2019 00:11:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bYddrydP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67B3220866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CFB8F6ECD7; Sat, 21 Dec 2019 00:11:55 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id C61BE6ECD2 for ; Sat, 21 Dec 2019 00:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576887112; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UpvjyHddomTBVlnRy5D6G8OJ5mZnjYRh6mZ8SNVnyW4=; b=bYddrydPknaQIsbkxy7H0+SbRkiJXGjDYvRsEtm1HdMbFR/ODT27bCu76DLzGLO+EXPxE9 RvUxa+bqO19DWPw0OohIILP0ZVcQY8xhCkiPfdlTMMyRYL6+viVgTc8xooDRx7YY5lRWIV VNiSqI6kA3A/j31fX5FBZiTwC/4OdVk= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-249-z9SV8-a7P7CfqFrIsiqGYg-1; Fri, 20 Dec 2019 19:11:50 -0500 Received: by mail-qk1-f198.google.com with SMTP id a6so4348586qkl.7 for ; Fri, 20 Dec 2019 16:11:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:organization:user-agent:mime-version :content-transfer-encoding; bh=UpvjyHddomTBVlnRy5D6G8OJ5mZnjYRh6mZ8SNVnyW4=; b=nC+UnfJdFv4xpSEEwY2OL1nooAPabRFAbq5T0Xi54CXjrl5RtE0Hrd81crklO/1ML3 6PwnCbukT6L4uckBVEnFwMOfVLOQQQs+a/RrkSgbNhoM4VKhNnYhTCwyWHFnsB7puywJ Grh2DyNhYraaXQTkVhR2EktFJNSnuAjfmeRSBe8etBC4ObIaGBNfSAiCDExOQop0yWhv 5t/m0NHGZYGr7uZdLhq6zFqsU1ZNAKseSqFl6QOjGeSupegDzUpI89ko9KwXr69En8+y bR5ljXfLE8fJlZ+OGmr2AQlz5UgPX+c5YklNPt2KJEbVZCtmGP8twiq7DyZXG/h0OhgA Hw0w== X-Gm-Message-State: APjAAAW8mLbdu0c2GN/GDOcBc7O+73OBH8xix78Rh8oxaUjFVEsrC4up OPyagZVQ026zL2+kUYDYM86PDvCiVvR6CBZSBS5a3C8Imt1Io4rs7blDoC2g7xj9rjxqwsDdVj5 fTcgtqYpULUaqgCUtZuxi3wELwKdf X-Received: by 2002:a05:620a:133a:: with SMTP id p26mr15607863qkj.233.1576887110300; Fri, 20 Dec 2019 16:11:50 -0800 (PST) X-Google-Smtp-Source: APXvYqwJw7kWbDwJzTxH+r2C3U8rbRcclU7cd3GFT2xwOnuXlYRM/9NpWWAyP0v0yC9CMPL8x0a/Cg== X-Received: by 2002:a05:620a:133a:: with SMTP id p26mr15607830qkj.233.1576887109935; Fri, 20 Dec 2019 16:11:49 -0800 (PST) Received: from dhcp-10-20-1-90.bss.redhat.com ([144.121.20.162]) by smtp.gmail.com with ESMTPSA id d143sm3364778qke.123.2019.12.20.16.11.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2019 16:11:49 -0800 (PST) Message-ID: <589e939efca5209af318645fa6799c423897eea6.camel@redhat.com> Subject: Re: [PATCH] drm/dp_mst: clear time slots for ports invalid From: Lyude Paul To: Wayne Lin , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org Date: Fri, 20 Dec 2019 19:11:48 -0500 In-Reply-To: <20191206083937.9411-1-Wayne.Lin@amd.com> References: <20191206083937.9411-1-Wayne.Lin@amd.com> Organization: Red Hat User-Agent: Evolution 3.34.2 (3.34.2-1.fc31) MIME-Version: 1.0 X-MC-Unique: z9SV8-a7P7CfqFrIsiqGYg-1 X-Mimecast-Spam-Score: 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: jerry.zuo@amd.com, Nicholas.Kazlauskas@amd.com, stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Mhh-I think I understand the problem you're trying to solve here but I think this solution might be a bit overkill. When I did the rework of topology references for ports, I made it so that we can guarantee memory access to a port without it needing to be a valid part of the topology. As well, all parents of the port are guaranteed to be accessible for as long as the child is. Take a look at: https://01.org/linuxgraphics/gfx-docs/drm/gpu/drm-kms-helpers.html#refcount-relationships-in-a-topology It's also worth noting that because of this there's a lot of get_port_validated()/put_port_validated() calls in the MST helpers that are now bogus and need to be removed once I get a chance. For new code we should limit the use of topology references to sections of code where we need a guarantee that resources on the port/branch (such as a drm connector, dp aux port, etc.) won't go away for as long as we need to use them. Do you think we could change this patch so instead of removing it from the proposed payloads on the CONNECTION_STATUS_NOTIFY, we keep the port's memory allocation around until it's been removed from the proposed payloads table and clean it up there on the next payload update? On Fri, 2019-12-06 at 16:39 +0800, Wayne Lin wrote: > [Why] > When change the connection status in a MST topology, mst device > which detect the event will send out CONNECTION_STATUS_NOTIFY messgae. > > e.g. src-mst-mst-sst => src-mst (unplug) mst-sst > > Currently, under the above case of unplugging device, ports which have > been allocated payloads and are no longer in the topology still occupy > time slots and recorded in proposed_vcpi[] of topology manager. > > If we don't clean up the proposed_vcpi[], when code flow goes to try to > update payload table by calling drm_dp_update_payload_part1(), we will > fail at checking port validation due to there are ports with proposed > time slots but no longer in the mst topology. As the result of that, we > will also stop updating the DPCD payload table of down stream port. > > [How] > While handling the CONNECTION_STATUS_NOTIFY message, add a detection to > see if the event indicates that a device is unplugged to an output port. > If the detection is true, then iterrate over all proposed_vcpi[] to > see whether a port of the proposed_vcpi[] is still in the topology or > not. If the port is invalid, set its num_slots to 0. > > Thereafter, when try to update payload table by calling > drm_dp_update_payload_part1(), we can successfully update the DPCD > payload table of down stream port and clear the proposed_vcpi[] to NULL. > > Signed-off-by: Wayne Lin > Cc: stable@vger.kernel.org > --- > drivers/gpu/drm/drm_dp_mst_topology.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c > b/drivers/gpu/drm/drm_dp_mst_topology.c > index 5306c47dc820..2e236b6275c4 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -2318,7 +2318,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch > *mstb, > { > struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; > struct drm_dp_mst_port *port; > - int old_ddps, ret; > + int old_ddps, old_input, ret, i; > u8 new_pdt; > bool dowork = false, create_connector = false; > > @@ -2349,6 +2349,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch > *mstb, > } > > old_ddps = port->ddps; > + old_input = port->input; > port->input = conn_stat->input_port; > port->mcs = conn_stat->message_capability_status; > port->ldps = conn_stat->legacy_device_plug_status; > @@ -2373,6 +2374,27 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch > *mstb, > dowork = false; > } > > + if (!old_input && old_ddps != port->ddps && !port->ddps) { > + for (i = 0; i < mgr->max_payloads; i++) { > + struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i]; > + struct drm_dp_mst_port *port_validated; > + > + if (vcpi) { > + port_validated = > + container_of(vcpi, struct > drm_dp_mst_port, vcpi); > + port_validated = > + drm_dp_mst_topology_get_port_validated > (mgr, port_validated); > + if (!port_validated) { > + mutex_lock(&mgr->payload_lock); > + vcpi->num_slots = 0; > + mutex_unlock(&mgr->payload_lock); > + } else { > + drm_dp_mst_topology_put_port(port_vali > dated); > + } > + } > + } > + } > + > if (port->connector) > drm_modeset_unlock(&mgr->base.lock); > else if (create_connector) -- Cheers, Lyude Paul _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel