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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham 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 516FEC432C0 for ; Sun, 24 Nov 2019 07:48:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27089207DD for ; Sun, 24 Nov 2019 07:48:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725948AbfKXHs5 (ORCPT ); Sun, 24 Nov 2019 02:48:57 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:36486 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725913AbfKXHs5 (ORCPT ); Sun, 24 Nov 2019 02:48:57 -0500 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:b93f:9fae:b276:a89a]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 862EB283BB9; Sun, 24 Nov 2019 07:48:52 +0000 (GMT) Date: Sun, 24 Nov 2019 08:48:48 +0100 From: Boris Brezillon To: Neil Armstrong Cc: dri-devel@lists.freedesktop.org, Lucas Stach , Chris Healy , Andrey Smirnov , Nikita Yushchenko , kernel@collabora.com, Daniel Vetter , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Thierry Reding , Sam Ravnborg , Philipp Zabel , Rob Clark , Andrzej Hajda , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Rob Herring , Mark Rutland , devicetree@vger.kernel.org Subject: Re: [PATCH v3 07/21] drm/bridge: Make the bridge chain a double-linked list Message-ID: <20191124084848.33a6bf01@collabora.com> In-Reply-To: References: <20191023154512.9762-1-boris.brezillon@collabora.com> <20191023154512.9762-8-boris.brezillon@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Neil, Sorry for the late reply. On Tue, 5 Nov 2019 17:02:30 +0100 Neil Armstrong wrote: > Hi, > > > On 25/10/2019 15:29, Neil Armstrong wrote: > > On 23/10/2019 17:44, Boris Brezillon wrote: > >> So that each element in the chain can easily access its predecessor. > >> This will be needed to support bus format negotiation between elements > >> of the bridge chain. > >> > >> Signed-off-by: Boris Brezillon > >> --- > >> Changes in v3: > >> * None > >> > >> Changes in v2: > >> * Adjust things to the "dummy encoder bridge" change (patch 2 in this > >> series) > >> --- > >> drivers/gpu/drm/drm_bridge.c | 171 ++++++++++++++++++++++------------ > >> drivers/gpu/drm/drm_encoder.c | 16 +--- > >> include/drm/drm_bridge.h | 12 ++- > >> include/drm/drm_encoder.h | 9 +- > >> 4 files changed, 135 insertions(+), 73 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > >> index 54c874493c57..c5cf8a9c4237 100644 > >> --- a/drivers/gpu/drm/drm_bridge.c > >> +++ b/drivers/gpu/drm/drm_bridge.c > > [...] > > >> > >> @@ -426,15 +471,23 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable); > >> void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge, > >> struct drm_atomic_state *state) > >> { > >> + struct drm_encoder *encoder; > >> + struct drm_bridge *iter; > >> + > >> if (!bridge) > >> return; > >> > >> - drm_atomic_bridge_chain_pre_enable(bridge->next, state); > >> + encoder = bridge->encoder; > >> + list_for_each_entry_reverse(iter, &bridge->encoder->bridge_chain, > >> + chain_node) { > > This should use the encoder local variable in list_for_each_entry_reverse() > > >> + if (iter->funcs->atomic_pre_enable) > >> + iter->funcs->atomic_pre_enable(iter, state); > >> + else if (iter->funcs->pre_enable) > >> + iter->funcs->pre_enable(iter); > >> > >> - if (bridge->funcs->atomic_pre_enable) > >> - bridge->funcs->atomic_pre_enable(bridge, state); > >> - else if (bridge->funcs->pre_enable) > >> - bridge->funcs->pre_enable(bridge); > >> + if (iter == bridge) > >> + break; > >> + } > >> } > >> EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable); > >> > >> @@ -453,15 +506,19 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable); > >> void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge, > >> struct drm_atomic_state *state) > >> { > >> + struct drm_encoder *encoder; > >> + > >> if (!bridge) > >> return; > >> > >> - if (bridge->funcs->atomic_enable) > >> - bridge->funcs->atomic_enable(bridge, state); > >> - else if (bridge->funcs->enable) > >> - bridge->funcs->enable(bridge); > >> - > >> - drm_atomic_bridge_chain_enable(bridge->next, state); > >> + encoder = bridge->encoder; > >> + list_for_each_entry_from(bridge, &bridge->encoder->bridge_chain, > >> + chain_node) { > > This should use encoder instead of bridge->encoder otherwise bridge will > change and bridge->encoder->bridge_chain won't be valid during the for_each and > cause the following : Oops, indeed. I fixed the very same problem in another helper but somehow missed those 2. Thanks for testing/reporting the bug. Boris