From patchwork Tue May 23 19:27:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13252837 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 26BC7C7EE26 for ; Tue, 23 May 2023 19:31:19 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AC98610E4AB; Tue, 23 May 2023 19:31:16 +0000 (UTC) Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by gabe.freedesktop.org (Postfix) with ESMTPS id C096F10E4A9 for ; Tue, 23 May 2023 19:31:13 +0000 (UTC) Received: by mail-pl1-x631.google.com with SMTP id d9443c01a7336-1a516fb6523so253875ad.3 for ; Tue, 23 May 2023 12:31:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1684870273; x=1687462273; 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=AKRK4xfTer6o8sAg3PoM2xcqa0uawxE5nHuVWKhZwR0=; b=F+RFRAAVkb14F3v0JkgcAWWjh6tAt8ecJgxOH0c24t+NptgnNpm3yQZQ4chcrhs6tm PmNunCCzD43Hl4JOutjqj+OkMvfjL9s/Hy5YtWhcfZCwQP+UezJfVTMEClILyKcpUTXP hSME9ktlQEYrUZ+NXyBfWVdcr5AxjahHC70oc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684870273; x=1687462273; 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=AKRK4xfTer6o8sAg3PoM2xcqa0uawxE5nHuVWKhZwR0=; b=ISz6Diza0/WM3waJEtzlxNdqu4h8p0/+13aGxchzanDUzgND+pJVN2gdtXj+hzzQRn bNJ9kiCd6CIIp06vA5fN6N1BTLpw4WeLsrEcEpn4GCTgzqXkT+aHoP4K5LQZuLjsll6J 5h5A3COtxIvtIAneHIlT7S2JKDIvSfC0X7AcTTrYn0Lj14H3mRYjT4ALaXh/rxyulc1x 02T2k4iiVLjGaM7Wz5puUls3usVLuFuRs7KO3dvPuGxuaBgj4tWxB+jVUV/InetBnbpk 2SDMNGsreTEXEFo5bG+WP3MnAOzXMITEgTwj14YKpcTZiOM7emfwxjY/okGeVGmJZ62i rK+A== X-Gm-Message-State: AC+VfDxMdjsB54cpOt+UXP6vY0scfP5Kfyz02L8M9AHmPIHJVMipsWVS zI5DJPdlL2uUXzOtpBmqBIFVbw== X-Google-Smtp-Source: ACHHUZ6+R5dtBFK1umveld97BEXM7URbVt+ovbFLPIhv1kkW0xyJu3i7kIBJg1vLIb01UTdBgQqzTg== X-Received: by 2002:a17:902:d2c2:b0:1ac:4412:bd9 with SMTP id n2-20020a170902d2c200b001ac44120bd9mr14843362plc.3.1684870272940; Tue, 23 May 2023 12:31:12 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:af98:af9d:ed15:f8b3]) by smtp.gmail.com with ESMTPSA id y18-20020a170902b49200b001aaef9d0102sm7109947plr.197.2023.05.23.12.31.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 May 2023 12:31:12 -0700 (PDT) From: Douglas Anderson To: Jiri Kosina , Benjamin Tissoires , Bjorn Andersson , Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Sam Ravnborg , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Subject: [PATCH 2/9] drm/panel: Check for already prepared/enabled in drm_panel Date: Tue, 23 May 2023 12:27:56 -0700 Message-ID: <20230523122802.2.I59b417d4c29151cc2eff053369ec4822b606f375@changeid> X-Mailer: git-send-email 2.40.1.698.g37aff9b760-goog In-Reply-To: <20230523193017.4109557-1-dianders@chromium.org> References: <20230523193017.4109557-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, cros-qcom-dts-watchers@chromium.org, linux-arm-msm@vger.kernel.org, yangcong5@huaqin.corp-partner.google.com, Dmitry Torokhov , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , linux-input@vger.kernel.org, hsinyi@google.com Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 Signed-off-by: Douglas Anderson Acked-by: Neil Armstrong --- 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,