From patchwork Thu Jan 27 20:01:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 12727251 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FF23C4167E for ; Thu, 27 Jan 2022 20:02:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343693AbiA0UCM (ORCPT ); Thu, 27 Jan 2022 15:02:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343669AbiA0UCG (ORCPT ); Thu, 27 Jan 2022 15:02:06 -0500 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3CBFC06174A for ; Thu, 27 Jan 2022 12:02:02 -0800 (PST) Received: by mail-pj1-x102e.google.com with SMTP id oa14-20020a17090b1bce00b001b61aed4a03so2803904pjb.5 for ; Thu, 27 Jan 2022 12:02:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Zwidypq4Go5OKqz8SmfacxJttUeteOhXrn3UaB5BhXk=; b=REahsmFv7SO2EJS19EQED429NY5ulcBzeS591w9Qh4Pq6DIrlxU+tNgz/zgHk4ndaQ WmxeguS5tRm+SlE5GaCWn5j2DmkfC+5tNTZZ21cjQj5J5I9mkVRp+aiMLbedeIhp/GB+ UotSKyXeCFEAFddTD58EeLeO4HL6mIql/DJrg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Zwidypq4Go5OKqz8SmfacxJttUeteOhXrn3UaB5BhXk=; b=hmS4wbUwN2J2RRbYUla+oAVbKfzQyrm1LM/PagJNYTLGnT/N1WziRu/OJO1YuQEBMv ME66aGugtKITqZY+g6Cb1X9Bhsz7uciJog5veyXZ2NUmxx3FB9kP9Z7nvTFb3FBYDuNa tVyrsX7QpjjvcCwhh1314wEWi2eqQSkr5EiCNPABVQt28zy85skl1IjBmSoc4mtS7iTp Ao61Y8wRtdMXiMPMMWP8CUfE4bEkyyudccfPFSunSCzn/GXSxOqGIT0W/uc4ITSp5ksO yomhzol5OKNl0IJ+KuRzQnHhm+N9VwenI4iqGD24FbHGP0ZioGb0I11Qh+v4AVZNMbiX o2jQ== X-Gm-Message-State: AOAM531JP849hLWFIGSDbIG/7AJKq95acFei2iXgQbKVYeV3TGbI17QE aeUZTTHD3fKWQtIuThQkVSlrCA== X-Google-Smtp-Source: ABdhPJyWAZjfirfkH7ymqHsj2L9OtTZWs6HiPoJtXWaYoR1/GX3EP0aYSGVsGYHdsaRFZkClJbP2WQ== X-Received: by 2002:a17:902:8c84:: with SMTP id t4mr2394992plo.78.1643313722210; Thu, 27 Jan 2022 12:02:02 -0800 (PST) Received: from smtp.gmail.com ([2620:15c:202:201:9246:1838:3243:3071]) by smtp.gmail.com with ESMTPSA id k21sm6561190pff.33.2022.01.27.12.02.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Jan 2022 12:02:01 -0800 (PST) From: Stephen Boyd To: Greg Kroah-Hartman , Douglas Anderson Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, Daniel Vetter , "Rafael J. Wysocki" , Rob Clark , Russell King , Saravana Kannan Subject: [PATCH v6 06/35] drm/msm: Migrate to aggregate driver Date: Thu, 27 Jan 2022 12:01:12 -0800 Message-Id: <20220127200141.1295328-7-swboyd@chromium.org> X-Mailer: git-send-email 2.35.0.rc0.227.g00780c9af4-goog In-Reply-To: <20220127200141.1295328-1-swboyd@chromium.org> References: <20220127200141.1295328-1-swboyd@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The device lists are poorly ordered when the component device code is used. This is because component_master_add_with_match() returns 0 regardless of component devices calling component_add() first. It can really only fail if an allocation fails, in which case everything is going bad and we're out of memory. The driver that registers the aggregate driver, can succeed at probe and put the attached device on the DPM lists before any of the component devices are probed and put on the lists. Within the component device framework this usually isn't that bad because the real driver work is done at bind time via component{,master}_ops::bind(). It becomes a problem when the driver core, or host driver, wants to operate on the component device outside of the bind/unbind functions, e.g. via 'remove' or 'shutdown'. The driver core doesn't understand the relationship between the host device and the component devices and could possibly try to operate on component devices when they're already removed from the system or shut down. Normally, device links or probe defer would reorder the lists and put devices that depend on other devices in the lists at the correct location, but with component devices this doesn't happen because this information isn't expressed anywhere. Drivers simply succeed at registering their component or the aggregate driver with the component framework and wait for their bind() callback to be called once the other components are ready. In summary, the drivers that make up the aggregate driver can probe in any order. This ordering problem becomes fairly obvious when shutting down the device with a DSI controller connected to a DSI bridge that is controlled via i2c. In this case, the msm display driver wants to tear down the display pipeline on shutdown via msm_pdev_shutdown() by calling drm_atomic_helper_shutdown(), and it can't do that unless the whole display chain is still probed and active in the system. When a display bridge is on i2c, the i2c device for the bridge will be created whenever the i2c controller probes, which could be before or after the msm display driver probes. If the i2c controller probes after the display driver, then the i2c controller will be shutdown before the display controller during system wide shutdown and thus i2c transactions will stop working before the display pipeline is shut down. This means we'll have the display bridge trying to access an i2c bus that's shut down because drm_atomic_helper_shutdown() is trying to disable the bridge after the bridge is off. The solution is to make the aggregate driver into a real struct driver that is bound to a device when the other component devices have all probed. Now that the component driver code is a proper bus, we can simply register an aggregate driver with that bus via component_aggregate_register() and then attach the shutdown hook to that driver to be sure that the shutdown for the display pipeline is called before any of the component device driver shutdown hooks are called. Cc: Daniel Vetter Cc: "Rafael J. Wysocki" Cc: Rob Clark Cc: Russell King Cc: Saravana Kannan Signed-off-by: Stephen Boyd --- drivers/gpu/drm/msm/msm_drv.c | 48 ++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index ad35a5d94053..32107e5cb547 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -1331,19 +1331,37 @@ static int add_gpu_components(struct device *dev, return 0; } -static int msm_drm_bind(struct device *dev) +static int msm_drm_bind(struct aggregate_device *adev) { - return msm_drm_init(dev, &msm_driver); + return msm_drm_init(aggregate_device_parent(adev), &msm_driver); } -static void msm_drm_unbind(struct device *dev) +static void msm_drm_unbind(struct aggregate_device *adev) { - msm_drm_uninit(dev); + msm_drm_uninit(aggregate_device_parent(adev)); +} + +static void msm_drm_shutdown(struct aggregate_device *adev) +{ + const struct device *parent = aggregate_device_parent(adev); + const struct platform_device *pdev = to_platform_device(parent); + struct msm_drm_private *priv = platform_get_drvdata(pdev); + struct drm_device *drm = priv ? priv->dev : NULL; + + if (!priv || !priv->kms) + return; + + drm_atomic_helper_shutdown(drm); } -static const struct component_master_ops msm_drm_ops = { - .bind = msm_drm_bind, - .unbind = msm_drm_unbind, +static struct aggregate_driver msm_drm_aggregate_driver = { + .probe = msm_drm_bind, + .remove = msm_drm_unbind, + .shutdown = msm_drm_shutdown, + .driver = { + .name = "msm_drm", + .owner = THIS_MODULE, + }, }; /* @@ -1395,7 +1413,7 @@ static int msm_pdev_probe(struct platform_device *pdev) if (ret) goto fail; - ret = component_master_add_with_match(&pdev->dev, &msm_drm_ops, match); + ret = component_aggregate_register(&pdev->dev, &msm_drm_aggregate_driver, match); if (ret) goto fail; @@ -1415,7 +1433,7 @@ static int msm_pdev_remove(struct platform_device *pdev) struct msm_drm_private *priv = platform_get_drvdata(pdev); struct msm_mdss *mdss = priv->mdss; - component_master_del(&pdev->dev, &msm_drm_ops); + component_aggregate_unregister(&pdev->dev, &msm_drm_aggregate_driver); of_platform_depopulate(&pdev->dev); if (mdss && mdss->funcs) @@ -1424,17 +1442,6 @@ static int msm_pdev_remove(struct platform_device *pdev) return 0; } -static void msm_pdev_shutdown(struct platform_device *pdev) -{ - struct msm_drm_private *priv = platform_get_drvdata(pdev); - struct drm_device *drm = priv ? priv->dev : NULL; - - if (!priv || !priv->kms) - return; - - drm_atomic_helper_shutdown(drm); -} - static const struct of_device_id dt_match[] = { { .compatible = "qcom,mdp4", .data = (void *)KMS_MDP4 }, { .compatible = "qcom,mdss", .data = (void *)KMS_MDP5 }, @@ -1450,7 +1457,6 @@ MODULE_DEVICE_TABLE(of, dt_match); static struct platform_driver msm_platform_driver = { .probe = msm_pdev_probe, .remove = msm_pdev_remove, - .shutdown = msm_pdev_shutdown, .driver = { .name = "msm", .of_match_table = dt_match,