From patchwork Fri Dec 27 14:41:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Brezillon X-Patchwork-Id: 11311251 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 06C47138D for ; Fri, 27 Dec 2019 14:41:37 +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 D82E420740 for ; Fri, 27 Dec 2019 14:41:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D82E420740 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.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 320256E108; Fri, 27 Dec 2019 14:41:33 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5A4F16E114 for ; Fri, 27 Dec 2019 14:41:32 +0000 (UTC) Received: from localhost.localdomain (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (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 D1E17292853; Fri, 27 Dec 2019 14:41:30 +0000 (GMT) From: Boris Brezillon To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Marek Szyprowski , Eric Anholt Subject: [PATCH 3/3] drm/exynos: dsi: Fix bridge chain handling Date: Fri, 27 Dec 2019 15:41:24 +0100 Message-Id: <20191227144124.210294-3-boris.brezillon@collabora.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191227144124.210294-1-boris.brezillon@collabora.com> References: <20191227144124.210294-1-boris.brezillon@collabora.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: Boris Brezillon , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Commit 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list") patched the bridge chain logic to use a double-linked list instead of a single-linked list. This change induced changes to the Exynos driver which was manually resetting the encoder->bridge element to NULL to control the enable/disable sequence of the bridge chain. During this conversion, 2 bugs were introduced: 1/ list_splice() was used to move chain elements to our own internal chain, but list_splice() does not reset the source list to an empty state, leading to unexpected bridge hook calls when drm_bridge_chain_xxx() helpers were called by the core. Replacing the list_splice() call by list_splice_init() fixes this problem. 2/ drm_bridge_chain_xxx() helpers operate on the bridge->encoder->bridge_chain list, which is now empty. When the helper uses list_for_each_entry_reverse() we end up with no operation done which is not what we want. But that's even worse when the helper uses list_for_each_entry_from(), because in that case we end up in an infinite loop searching for the list head element which is no longer encoder->bridge_chain but exynos_dsi->bridge_chain. To address that problem we stop using the bridge chain helpers and call the hooks directly. Reported-by: Marek Szyprowski Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list") Signed-off-by: Boris Brezillon Tested-by: Marek Szyprowski Reviewed-by: Andrzej Hajda --- Hello Marek, I'm perfectly fine applying your patch instead of this one if you prefer to restrict the logic to a single bridge per chain. I just sent this patch in case your okay with the slightly different version I propose here. Let me know what you want to do. Regards, Boris --- drivers/gpu/drm/exynos/exynos_drm_dsi.c | 29 ++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index 3955f84dc893..33628d85edad 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -1378,6 +1378,7 @@ static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi) static void exynos_dsi_enable(struct drm_encoder *encoder) { struct exynos_dsi *dsi = encoder_to_dsi(encoder); + struct drm_bridge *iter; int ret; if (dsi->state & DSIM_STATE_ENABLED) @@ -1391,7 +1392,11 @@ static void exynos_dsi_enable(struct drm_encoder *encoder) if (ret < 0) goto err_put_sync; } else { - drm_bridge_chain_pre_enable(dsi->out_bridge); + list_for_each_entry_reverse(iter, &dsi->bridge_chain, + chain_node) { + if (iter->funcs->pre_enable) + iter->funcs->pre_enable(iter); + } } exynos_dsi_set_display_mode(dsi); @@ -1402,7 +1407,10 @@ static void exynos_dsi_enable(struct drm_encoder *encoder) if (ret < 0) goto err_display_disable; } else { - drm_bridge_chain_enable(dsi->out_bridge); + list_for_each_entry(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->enable) + iter->funcs->enable(iter); + } } dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE; @@ -1420,6 +1428,7 @@ static void exynos_dsi_enable(struct drm_encoder *encoder) static void exynos_dsi_disable(struct drm_encoder *encoder) { struct exynos_dsi *dsi = encoder_to_dsi(encoder); + struct drm_bridge *iter; if (!(dsi->state & DSIM_STATE_ENABLED)) return; @@ -1427,10 +1436,20 @@ static void exynos_dsi_disable(struct drm_encoder *encoder) dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE; drm_panel_disable(dsi->panel); - drm_bridge_chain_disable(dsi->out_bridge); + + list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->disable) + iter->funcs->disable(iter); + } + exynos_dsi_set_display_enable(dsi, false); drm_panel_unprepare(dsi->panel); - drm_bridge_chain_post_disable(dsi->out_bridge); + + list_for_each_entry(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->post_disable) + iter->funcs->post_disable(iter); + } + dsi->state &= ~DSIM_STATE_ENABLED; pm_runtime_put_sync(dsi->dev); } @@ -1523,7 +1542,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host, if (out_bridge) { drm_bridge_attach(encoder, out_bridge, NULL); dsi->out_bridge = out_bridge; - list_splice(&encoder->bridge_chain, &dsi->bridge_chain); + list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain); } else { int ret = exynos_dsi_create_connector(encoder);