From patchwork Thu Dec 2 22:27:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 12653563 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 D9C38C433F5 for ; Thu, 2 Dec 2021 22:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377190AbhLBWbH (ORCPT ); Thu, 2 Dec 2021 17:31:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356376AbhLBWbF (ORCPT ); Thu, 2 Dec 2021 17:31:05 -0500 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0037C06174A for ; Thu, 2 Dec 2021 14:27:42 -0800 (PST) Received: by mail-pf1-x436.google.com with SMTP id g18so958960pfk.5 for ; Thu, 02 Dec 2021 14:27:42 -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=MLFo5uJ88/q78BTGkhEJmKSkKMysd8HwfQglPXTN2wU=; b=YOIWSmyXUC1gwfBg+mxcJI6bLd1QZuk7ZXAp8JtJ8Rx4P6txp6z2xi2PJpbwbIzcrE T2gZqoGJYJHR3UkQ00XqRplYmb6aGolq68S0za0jKVARthPRWJ2BaC2wHe9dQme4dlZP qq1ERd7mragzTa02G2Ol6b/9pOTXvUHz1gp4s= 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=MLFo5uJ88/q78BTGkhEJmKSkKMysd8HwfQglPXTN2wU=; b=FftXzMgBp9AxWCqTnx+sH0+zAXJztekBQrDx3bR6GUrUCmZlTzSMccIwIgVEc0ZdL6 rwFvBnZEMV4MDT+RFP2u5JE4Ei3G043XUOsRuR/ZTd+a2lPzK1fiRcyAJXpJBe6X+I31 yCUYHQU2Xj0k9/1dj8uvJbZNEHO3Pxp6P9mkgMzw5svxMNnI7hH7h/LmOHgqOzfWXCAm CImEqAMeHg0mqYt+nq+zouEtep7808Z1Vcuknwj3mioUCr1xvieS1DYMKgm+LTgWoB2q ME7S9ET0paMP8WxFCcnV1wAtxOIJ/lbVWo4CIyxD62+nq1wc3zpFHAt2J1g1AKVBfCfZ CORg== X-Gm-Message-State: AOAM532HYdLOvg4HX0hNYGhfCUR7WIGJuyv744g/2uVTl2lE0zv/+uKv R79sJkB8y+oAy/EiTqpQNLayQg== X-Google-Smtp-Source: ABdhPJwllu4eSCuzfr6fRf0Jpy2tTgWg6gjx2VzA44DzgUx5jyEEuWVialv1QGChSerhR2xWJyioHg== X-Received: by 2002:a63:904a:: with SMTP id a71mr1528938pge.241.1638484062175; Thu, 02 Dec 2021 14:27:42 -0800 (PST) Received: from smtp.gmail.com ([2620:15c:202:201:f4f2:1b7e:5aea:bf3c]) by smtp.gmail.com with ESMTPSA id q9sm836934pfj.9.2021.12.02.14.27.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Dec 2021 14:27:41 -0800 (PST) From: Stephen Boyd To: Greg Kroah-Hartman 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 v4 07/34] drm/msm: Migrate to aggregate driver Date: Thu, 2 Dec 2021 14:27:05 -0800 Message-Id: <20211202222732.2453851-8-swboyd@chromium.org> X-Mailer: git-send-email 2.34.0.384.gca35af8252-goog In-Reply-To: <20211202222732.2453851-1-swboyd@chromium.org> References: <20211202222732.2453851-1-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 | 46 +++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 7936e8d498dd..f6e9b0d318f5 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -1360,19 +1360,35 @@ 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(adev->parent, &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(adev->parent); +} + +static void msm_drm_shutdown(struct aggregate_device *adev) +{ + struct drm_device *drm = platform_get_drvdata(to_platform_device(adev->parent)); + struct msm_drm_private *priv = drm ? drm->dev_private : 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, + }, }; /* @@ -1401,7 +1417,7 @@ 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; @@ -1414,23 +1430,12 @@ static int msm_pdev_probe(struct platform_device *pdev) static int msm_pdev_remove(struct platform_device *pdev) { - component_master_del(&pdev->dev, &msm_drm_ops); + component_aggregate_unregister(&pdev->dev, &msm_drm_aggregate_driver); of_platform_depopulate(&pdev->dev); return 0; } -static void msm_pdev_shutdown(struct platform_device *pdev) -{ - struct drm_device *drm = platform_get_drvdata(pdev); - struct msm_drm_private *priv = drm ? drm->dev_private : 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 }, @@ -1446,7 +1451,6 @@ 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,