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[2620:137:e000::1:20]) by mx.google.com with ESMTP id p22-20020a63c156000000b0053f27c5efe4si9073610pgi.857.2023.06.07.14.54.22; Wed, 07 Jun 2023 14:54:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=ayuR0NPM; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230104AbjFGVxV (ORCPT + 99 others); Wed, 7 Jun 2023 17:53:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232093AbjFGVxN (ORCPT ); Wed, 7 Jun 2023 17:53:13 -0400 Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A32711FD6 for ; Wed, 7 Jun 2023 14:53:11 -0700 (PDT) Received: by mail-pf1-x435.google.com with SMTP id d2e1a72fcca58-654f8b56807so5319111b3a.1 for ; Wed, 07 Jun 2023 14:53:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1686174791; x=1688766791; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=hfUG9c2qlt8kTNqx7t/idPYkBIfLX/cfnxD2deWf3W8=; b=ayuR0NPMX0lCr649Ls3PcdaWJi3/pI5z6ekASxp9r2pXuUPRAKtIyY930QFx1kuFcE nOzUI88ocCNkotOwnkN5ZtWTSMimth7YMeld2HFSmbDacRlogFUCdDed5mPLGt0c4lYC KN5LqNcDew/hCZof0SBt6j5tLIkYGt873vkRE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686174791; x=1688766791; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=hfUG9c2qlt8kTNqx7t/idPYkBIfLX/cfnxD2deWf3W8=; b=FU/kGR01/oElkQWD4l7I21RpUTsec33nlqneT8laNhp4pOqjPFze+EX9EiKoR/xz/w n08eD3WTk/CDohAlXRZM7WZVxYOlcQcWHacsOgOipKh53n+4+kJIRfCFbMWSHInFiTfI vEzQrwIp1pmzUTh5pNxMdg0L0CnX9Xxb/IgTM17CcdQ4g8fz7VmgJQbuEovSjhkshEJu HRcrCbeU0dn3/0esoGZUb6iU+K2UyO50kz3TD1T4S3Hy7x92KSHBDY3DAbI+Iza+Mft9 A6+Fc3A8+iN5M9ExVqp3foR97thLndteWOC7BU3Sau/OVMmb/O4OzF6YHoBCdHucDhVx lulQ== X-Gm-Message-State: AC+VfDx/6drmhoTN2OtVjqTpPRrJtX5beercZp1COVhjO1Tt6C19HNXq YQqQMurczxxUiw3PFQMgnBaD12jMrAWSZC/2PV8= X-Received: by 2002:a05:6a20:8f17:b0:107:1805:feea with SMTP id b23-20020a056a208f1700b001071805feeamr5073223pzk.37.1686174791064; Wed, 07 Jun 2023 14:53:11 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:34b2:b638:6b53:f6c2]) by smtp.gmail.com with ESMTPSA id j25-20020aa78d19000000b0065dd1e7c2c1sm1376486pfe.63.2023.06.07.14.53.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jun 2023 14:53:10 -0700 (PDT) From: Douglas Anderson To: Jiri Kosina , Benjamin Tissoires , Bjorn Andersson , Konrad Dybcio , Rob Herring , Frank Rowand , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Sam Ravnborg , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Cc: dri-devel@lists.freedesktop.org, Dmitry Torokhov , linux-input@vger.kernel.org, Daniel Vetter , linux-kernel@vger.kernel.org, hsinyi@google.com, cros-qcom-dts-watchers@chromium.org, devicetree@vger.kernel.org, yangcong5@huaqin.corp-partner.google.com, linux-arm-msm@vger.kernel.org, Chris Morgan , Douglas Anderson Subject: [PATCH v2 02/10] drm/panel: Check for already prepared/enabled in drm_panel Date: Wed, 7 Jun 2023 14:49:24 -0700 Message-ID: <20230607144931.v2.2.I59b417d4c29151cc2eff053369ec4822b606f375@changeid> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog In-Reply-To: <20230607215224.2067679-1-dianders@chromium.org> References: <20230607215224.2067679-1-dianders@chromium.org> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768082506155131888?= X-GMAIL-MSGID: =?utf-8?q?1768082506155131888?= In a whole pile of panel drivers, we have code to make the prepare/unprepare/enable/disable callbacks behave as no-ops if they've already been called. It's silly to have this code duplicated everywhere. Add it to the core instead so that we can eventually delete it from all the drivers. Note: to get some idea of the duplicated code, try: git grep 'if.*>prepared' -- drivers/gpu/drm/panel git grep 'if.*>enabled' -- drivers/gpu/drm/panel NOTE: arguably, the right thing to do here is actually to skip this patch and simply remove all the extra checks from the individual drivers. Perhaps the checks were needed at some point in time in the past but maybe they no longer are? Certainly as we continue transitioning over to "panel_bridge" then we expect there to be much less variety in how these calls are made. When we're called as part of the bridge chain, things should be pretty simple. In fact, there was some discussion in the past about these checks [1], including a discussion about whether the checks were needed and whether the calls ought to be refcounted. At the time, I decided not to mess with it because it felt too risky. Looking closer at it now, I'm fairly certain that nothing in the existing codebase is expecting these calls to be refcounted. The only real question is whether someone is already doing something to ensure prepare()/unprepare() match and enabled()/disable() match. I would say that, even if there is something else ensuring that things match, there's enough complexity that adding an extra bool and an extra double-check here is a good idea. Let's add a drm_warn() to let people know that it's considered a minor error to take advantage of drm_panel's double-checking but we'll still make things work fine. [1] https://lore.kernel.org/r/20210416153909.v4.27.I502f2a92ddd36c3d28d014dd75e170c2d405a0a5@changeid Acked-by: Neil Armstrong Signed-off-by: Douglas Anderson --- This has Neil's Ack and I could commit it to drm-misc-next, but for now I'm holding off to see where this series ends up. If the series ends up looking good we'll have to coordinate landing the various bits between the drm and the hid trees and the second drm patch in my series depends on this one. If my series implodes I'll land this one on its own. In any case, once this lands somewhere I'll take an AI to cleanup the panels. (no changes since v1) drivers/gpu/drm/drm_panel.c | 49 ++++++++++++++++++++++++++++++++----- include/drm/drm_panel.h | 14 +++++++++++ 2 files changed, 57 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index f634371c717a..4e1c4e42575b 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -105,11 +105,22 @@ EXPORT_SYMBOL(drm_panel_remove); */ int drm_panel_prepare(struct drm_panel *panel) { + int ret; + if (!panel) return -EINVAL; - if (panel->funcs && panel->funcs->prepare) - return panel->funcs->prepare(panel); + if (panel->prepared) { + dev_warn(panel->dev, "Skipping prepare of already prepared panel\n"); + return 0; + } + + if (panel->funcs && panel->funcs->prepare) { + ret = panel->funcs->prepare(panel); + if (ret < 0) + return ret; + } + panel->prepared = true; return 0; } @@ -128,11 +139,22 @@ EXPORT_SYMBOL(drm_panel_prepare); */ int drm_panel_unprepare(struct drm_panel *panel) { + int ret; + if (!panel) return -EINVAL; - if (panel->funcs && panel->funcs->unprepare) - return panel->funcs->unprepare(panel); + if (!panel->prepared) { + dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n"); + return 0; + } + + if (panel->funcs && panel->funcs->unprepare) { + ret = panel->funcs->unprepare(panel); + if (ret < 0) + return ret; + } + panel->prepared = false; return 0; } @@ -155,11 +177,17 @@ int drm_panel_enable(struct drm_panel *panel) if (!panel) return -EINVAL; + if (panel->enabled) { + dev_warn(panel->dev, "Skipping enable of already enabled panel\n"); + return 0; + } + if (panel->funcs && panel->funcs->enable) { ret = panel->funcs->enable(panel); if (ret < 0) return ret; } + panel->enabled = true; ret = backlight_enable(panel->backlight); if (ret < 0) @@ -187,13 +215,22 @@ int drm_panel_disable(struct drm_panel *panel) if (!panel) return -EINVAL; + if (!panel->enabled) { + dev_warn(panel->dev, "Skipping disable of already disabled panel\n"); + return 0; + } + ret = backlight_disable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", ret); - if (panel->funcs && panel->funcs->disable) - return panel->funcs->disable(panel); + if (panel->funcs && panel->funcs->disable) { + ret = panel->funcs->disable(panel); + if (ret < 0) + return ret; + } + panel->enabled = false; return 0; } diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 432fab2347eb..c6cf75909389 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -198,6 +198,20 @@ struct drm_panel { * the panel is powered up. */ bool prepare_prev_first; + + /** + * @prepared: + * + * If true then the panel has been prepared. + */ + bool prepared; + + /** + * @enabled: + * + * If true then the panel has been enabled. + */ + bool enabled; }; void drm_panel_init(struct drm_panel *panel, struct device *dev,