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=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 2130EC433E4 for ; Fri, 10 Jul 2020 23:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F149020657 for ; Fri, 10 Jul 2020 23:02:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="eSk70hMU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726729AbgGJXCp (ORCPT ); Fri, 10 Jul 2020 19:02:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726523AbgGJXCp (ORCPT ); Fri, 10 Jul 2020 19:02:45 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37B6BC08E6DC for ; Fri, 10 Jul 2020 16:02:45 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id k71so3225494pje.0 for ; Fri, 10 Jul 2020 16:02:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=lCcFDIfWLkWWzSa31vXd7WJo8Tj5ziQlVQDdDR7C5oY=; b=eSk70hMUPgz/3k9+jsUUcyV/2ls1oSHGujFrad521MpLwNTFi3jkIVTuxh/psq9MFB gSIBJUNMurjt6JR179DwAKtpBcb2MiH1TvrZsLOlNzPYmhQrjv4tVtyc47GV5lmLb02U Y1r1UkBY004HeQ7oKUtQr8gSgIwbtrc7TluJM= 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:mime-version :content-transfer-encoding; bh=lCcFDIfWLkWWzSa31vXd7WJo8Tj5ziQlVQDdDR7C5oY=; b=H6giCXc63DOfy8rFp4OT79aPv/Pe/n5eLM1LIzgzBkcavD/CwygwClVzpZCHhKw20x cz5n5iqLTsz8aDDq8nRLH0xUjAbfY2/8+csprVnumKbD1hfGnsFQfSJP0O1lBmeySesu m7kSuhZGEAT4VNxBlJao+A0mib7q/fsbA9ReCk4IQmFpCY1CoZVWNoEIZnrearkJi0WV KbTndZUc8QBsGHnHU0qNaWaU6Wxk0dSSUslVTibyaer5dD/Ob5FHRL+BaAmLGZDHnu/B ga8P1UqEayp/SbaSPjF+xA8/XAAnw0u9HkcXbuOXk+n2xfGFlCdDK7/ArRuH8xPvzLMy u0jA== X-Gm-Message-State: AOAM5339I7vswcSO5/RvU+0apXEQdxyKP9rGKKTeMIEQRqoIWoUwXnaR wY3WaSZV8XnYsooM+o2YKDMoSw== X-Google-Smtp-Source: ABdhPJz0vohhKOdR4S48Go6SbBkYwUYpvNGQCHrL60amRJ3jBZ6fmwC9ItCPgsI2PgpcjlqG0gq6pA== X-Received: by 2002:a17:902:bb82:: with SMTP id m2mr4020800pls.61.1594422164622; Fri, 10 Jul 2020 16:02:44 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:42b0:34ff:fe3d:58e6]) by smtp.gmail.com with ESMTPSA id my9sm7266836pjb.44.2020.07.10.16.02.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2020 16:02:44 -0700 (PDT) From: Douglas Anderson To: Rob Herring , Rob Clark , Sean Paul , Andy Gross , Bjorn Andersson Cc: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org, Douglas Anderson , Daniel Vetter , David Airlie , linux-kernel@vger.kernel.org Subject: [PATCH 0/9] drm/msm: Avoid possible infinite probe deferral and speed booting Date: Fri, 10 Jul 2020 16:02:15 -0700 Message-Id: <20200710230224.2265647-1-dianders@chromium.org> X-Mailer: git-send-email 2.27.0.383.g050319c2ae-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I found that if I ever had a little mistake in my kernel config, or device tree, or graphics driver that my system would sit in a loop at bootup trying again and again and again. An example log was: msm ae00000.mdss: bound ae01000.mdp (ops 0xffffffe596e951f8) msm_dsi ae94000.dsi: ae94000.dsi supply gdsc not found, using dummy regulator msm_dsi_manager_register: failed to register mipi dsi host for DSI 0 [drm:ti_sn_bridge_probe] *ERROR* could not find any panel node ... I finally tracked it down where this was happening: - msm_pdev_probe() is called. - msm_pdev_probe() registers drivers. Registering drivers kicks off processing of probe deferrals. - component_master_add_with_match() could return -EPROBE_DEFER. making msm_pdev_probe() return -EPROBE_DEFER. - When msm_pdev_probe() returned the processing of probe deferrals happens. - Loop back to the start. It looks like we can fix this by marking "mdss" as a "simple-bus". I have no idea if people consider this the right thing to do or a hack. Hopefully it's the right thing to do. :-) Once I do this I notice that my boot gets marginally faster (you don't need to probe the sub devices over and over) and also if I have a problem it doesn't loop forever (on my system it still gets upset about some stuck clocks in that case, but at least I can boot up). Unless someone hates this, I'd expect: - Get Rob H to say that the bindings are OK (if they are) and yell that these really need to be converted to yaml (they do). - Get Sean or Rob C to land the bindings and driver patch. - Get Andy or Bjorn to land the dts bits. NOTES: - The first patch could land either way. It's just a cleanup. - I tried to split the dts files into separate patches to ease backporting if desired. Also because I can't actually test most of this hardware myself. Douglas Anderson (9): drm/msm: Use the devm variant of of_platform_populate() dt-bindings: msm/dpu: Add simple-bus to dpu bindings dt-bindings: msm/mdp5: Add simple-bus to dpu bindings drm/msm: Avoid manually populating our children if "simple-bus" is there arm64: dts: qcom: sc7180: Add "simple-bus" to our mdss node arm64: dts: qcom: sdm845: Add "simple-bus" to our mdss node arm64: dts: qcom: msm8916: Add "simple-bus" to our mdss node arm64: dts: qcom: msm8996: Add "simple-bus" to our mdss node ARM: dts: qcom: msm8974: Add "simple-bus" to our mdss node .../devicetree/bindings/display/msm/dpu.txt | 4 ++- .../devicetree/bindings/display/msm/mdp5.txt | 2 +- arch/arm/boot/dts/qcom-msm8974.dtsi | 2 +- arch/arm64/boot/dts/qcom/msm8916.dtsi | 2 +- arch/arm64/boot/dts/qcom/msm8996.dtsi | 2 +- arch/arm64/boot/dts/qcom/sc7180.dtsi | 2 +- arch/arm64/boot/dts/qcom/sdm845.dtsi | 2 +- drivers/gpu/drm/msm/msm_drv.c | 34 ++++++++----------- 8 files changed, 24 insertions(+), 26 deletions(-) -- 2.27.0.383.g050319c2ae-goog