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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 A666AC433DB for ; Sun, 14 Feb 2021 19:43:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AD4264DE0 for ; Sun, 14 Feb 2021 19:43:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229992AbhBNTm4 (ORCPT ); Sun, 14 Feb 2021 14:42:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229974AbhBNTml (ORCPT ); Sun, 14 Feb 2021 14:42:41 -0500 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 656BAC06178A for ; Sun, 14 Feb 2021 11:41:40 -0800 (PST) Received: by mail-pj1-x102b.google.com with SMTP id gb24so2482643pjb.4 for ; Sun, 14 Feb 2021 11:41:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amarulasolutions.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uYz3kOtrZ6Hf5DjXT1UkBRogQ4J1lPOvWIWH1kd6QXA=; b=aO2QjQGa2mG9vCy1BwYu3zPMtnftm5Mg2AM9uV8EZImKreIS9VatNBo8bb0qRtNplE 3OBD8aDO1PGAaH8XGG16wdFBOCLqqTx5nMR5pn1I8GBZO4l4CssVedKyRpXL6TVYrtw6 TcovWJ3IIlzD1+m8i7Q6j4uqUZI5AThOLWvR4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uYz3kOtrZ6Hf5DjXT1UkBRogQ4J1lPOvWIWH1kd6QXA=; b=Z+Q5J4e1NyKCDa++UmNJugReIbmvq+DhLZuThVaAu0kOpeuztznccgXwbAli50gAHQ 3hkm4saFmJObDWsjXQnIWwRo557l/bb/PDOAO/UI74bw4Bm83vGpakc/UKUlLcBRo5Mt Nolni6/KYDau24qmr3Q2LH1lR5aLk0exeSF2oLPLCWS4mdkjPgST0B6jKlY2+473UT8A DA13DUs4JrlI07bewB7t6lT2d12mjEoQ2zM4adS8V0K7rYd2rDZhZ+5MfzTaWuGkPTZ2 GFUDrFAbCy5kH+4ojjiksrJTWrpdrbSqscxcVg+jn7GZotHBMrzIrEs4zUdb9fawdLWM BYDQ== X-Gm-Message-State: AOAM532rfnztPWzEmuoxz9/7bGHvJCUSKDArbxQcirSLLn/6we+J8LjA wYgsGo/wSrZxax59GTMIdzWkMw== X-Google-Smtp-Source: ABdhPJzLLpSe6h6YLhCLR1f9osYYHY7qcokxZFU5wgjVcteYh/v71KLAWqCEIpbS89QnvAza0juNXg== X-Received: by 2002:a17:90b:4d06:: with SMTP id mw6mr12223997pjb.24.1613331699994; Sun, 14 Feb 2021 11:41:39 -0800 (PST) Received: from ub-XPS-13-9350.domain.name ([45.249.78.214]) by smtp.gmail.com with ESMTPSA id 125sm15129247pfu.7.2021.02.14.11.41.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 14 Feb 2021 11:41:39 -0800 (PST) From: Jagan Teki To: Maxime Ripard , Chen-Yu Tsai , Jernej Skrabec , Laurent Pinchart Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-amarula@amarulasolutions.com, Jagan Teki , Maarten Lankhorst , Thomas Zimmermann Subject: [PATCH v3 5/7] drm: bridge: Queue the bridge chain instead of stacking Date: Mon, 15 Feb 2021 01:11:00 +0530 Message-Id: <20210214194102.126146-6-jagan@amarulasolutions.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210214194102.126146-1-jagan@amarulasolutions.com> References: <20210214194102.126146-1-jagan@amarulasolutions.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org drm_bridge_attach has stacked the bridge chain, so the bridge that gets pushed last can trigger its bridge function pre_enable first from drm_atomic_bridge_chain_pre_enable. This indeed gives a chance to trigger slave bridge pre_enable first without triggering its host bridge pre_enable for the usual host to slave device model like DSI host with panel slave. For fully enabled bridge drivers, host bridge pre_enable has all host related clock, reset, PHY configuration code that needs to initialized before sending commands or configuration from a slave to communicate its host. Queue the bridge chain instead of stacking it so-that the bridges that got enqueued first can have a chance to trigger first. Cc: Maarten Lankhorst Cc: Thomas Zimmermann Signed-off-by: Jagan Teki --- Changes for v3: - new patch drivers/gpu/drm/drm_bridge.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 64f0effb52ac..e75d1a080c55 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -191,9 +191,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, bridge->encoder = encoder; if (previous) - list_add(&bridge->chain_node, &previous->chain_node); + list_add_tail(&bridge->chain_node, &previous->chain_node); else - list_add(&bridge->chain_node, &encoder->bridge_chain); + list_add_tail(&bridge->chain_node, &encoder->bridge_chain); if (bridge->funcs->attach) { ret = bridge->funcs->attach(bridge, flags); -- 2.25.1