From patchwork Wed Dec 23 12:55:22 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yakir Yang X-Patchwork-Id: 7912141 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 04CEE9F1AF for ; Wed, 23 Dec 2015 12:59:21 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E5BB9204AE for ; Wed, 23 Dec 2015 12:59:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DDDCA20444 for ; Wed, 23 Dec 2015 12:59:18 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aBizO-0001G6-MB; Wed, 23 Dec 2015 12:57:58 +0000 Received: from lucky1.263xmail.com ([211.157.147.133]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aBizK-00012g-6W; Wed, 23 Dec 2015 12:57:55 +0000 Received: from ykk?rock-chips.com (unknown [192.168.167.158]) by lucky1.263xmail.com (Postfix) with SMTP id 5AC174E981; Wed, 23 Dec 2015 20:57:30 +0800 (CST) X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.263.net (Postfix) with ESMTP id 9057E2AD47; Wed, 23 Dec 2015 20:57:24 +0800 (CST) X-RL-SENDER: ykk@rock-chips.com X-FST-TO: inki.dae@samsung.com X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: ykk@rock-chips.com X-UNIQUE-TAG: <7ac4cc07082ba4bcf582a3ca06b6919e> X-ATTACHMENT-NUM: 0 X-SENDER: ykk@rock-chips.com X-DNS-TYPE: 0 Received: from localhost.localdomain (unknown [58.22.7.114]) by smtp.263.net (Postfix) whith ESMTP id 12325R5CGWZ; Wed, 23 Dec 2015 20:57:26 +0800 (CST) From: Yakir Yang To: Inki Dae , Mark Yao , Jingoo Han , Heiko Stuebner Subject: [PATCH v12 18/18] drm: bridge: analogix/dp: Fix the possible dead lock in bridge disable time Date: Wed, 23 Dec 2015 20:55:22 +0800 Message-Id: <1450875322-19728-1-git-send-email-ykk@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450873538-18304-1-git-send-email-ykk@rock-chips.com> References: <1450873538-18304-1-git-send-email-ykk@rock-chips.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151223_045754_806024_DAB8C4F9 X-CRM114-Status: GOOD ( 15.23 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org, Russell King , linux-rockchip@lists.infradead.org, emil.l.velikov@gmail.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Kishon Vijay Abraham I , javier@osg.samsung.com, Rob Herring , Yakir Yang , Andy Yan , Thierry Reding , Gustavo Padovan , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It may caused a dead lock if we flush the hpd work in bridge disable time. The normal flow would like: IN --> DRM IOCTL 1. Acquire crtc_ww_class_mutex (DRM IOCTL) IN --> analogix_dp_bridge 2. Acquire hpd work lock (Flush hpd work) 3. HPD work already in idle, no need to run the work function. OUT <-- analogix_dp_bridge OUT <-- DRM IOCTL The dead lock flow would like: IN --> DRM IOCTL 1. Acquire crtc_ww_class_mutex (DRM IOCTL) IN --> analogix_dp_bridge 2. Acquire hpd work lock (Flush hpd work) IN --> analogix_dp_hotplug IN --> drm_helper_hpd_irq_event 3. Acquire mode_config lock (This lock already have been acquired in previous step 1) ** Dead Lock Now ** It's wrong to flush the hpd work in bridge->disable time, I guess the original code just want to ensure the delay work must be finish before encoder disabled. The flush work in bridge disable time is try to ensure the HPD event won't be missed before display card disabled, actually we can take a fast respond way(interrupt thread) to update DRM HPD event to fix the delay update and possible dead lock. Signed-off-by: Yakir Yang --- Changes in v12: None Changes in v11: None Changes in v10: None Changes in v9: None Changes in v8: None Changes in v7: None Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 62 ++++++++++------------ drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 3 +- drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 26 +++++++++ 3 files changed, 55 insertions(+), 36 deletions(-) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index 1e98489..04efed2 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -851,47 +851,40 @@ static void analogix_dp_enable_scramble(struct analogix_dp_device *dp, } } -static irqreturn_t analogix_dp_irq_handler(int irq, void *arg) +static irqreturn_t analogix_dp_hardirq(int irq, void *arg) { struct analogix_dp_device *dp = arg; - + irqreturn_t ret = IRQ_NONE; enum dp_irq_type irq_type; irq_type = analogix_dp_get_irq_type(dp); - switch (irq_type) { - case DP_IRQ_TYPE_HP_CABLE_IN: - dev_dbg(dp->dev, "Received irq - cable in\n"); - schedule_work(&dp->hotplug_work); - analogix_dp_clear_hotplug_interrupts(dp); - break; - case DP_IRQ_TYPE_HP_CABLE_OUT: - dev_dbg(dp->dev, "Received irq - cable out\n"); - analogix_dp_clear_hotplug_interrupts(dp); - break; - case DP_IRQ_TYPE_HP_CHANGE: - /* - * We get these change notifications once in a while, but there - * is nothing we can do with them. Just ignore it for now and - * only handle cable changes. - */ - dev_dbg(dp->dev, "Received irq - hotplug change; ignoring.\n"); - analogix_dp_clear_hotplug_interrupts(dp); - break; - default: - dev_err(dp->dev, "Received irq - unknown type!\n"); - break; + if (irq_type != DP_IRQ_TYPE_UNKNOWN) { + analogix_dp_mute_hpd_interrupt(dp); + ret = IRQ_WAKE_THREAD; } - return IRQ_HANDLED; + + return ret; } -static void analogix_dp_hotplug(struct work_struct *work) +static irqreturn_t analogix_dp_irq_thread(int irq, void *arg) { - struct analogix_dp_device *dp; + struct analogix_dp_device *dp = arg; + enum dp_irq_type irq_type; + + irq_type = analogix_dp_get_irq_type(dp); + if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN || + irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) { + dev_dbg(dp->dev, "Detected cable status changed!\n"); + if (dp->drm_dev) + drm_helper_hpd_irq_event(dp->drm_dev); + } - dp = container_of(work, struct analogix_dp_device, hotplug_work); + if (irq_type != DP_IRQ_TYPE_UNKNOWN) { + analogix_dp_clear_hotplug_interrupts(dp); + analogix_dp_unmute_hpd_interrupt(dp); + } - if (dp->drm_dev) - drm_helper_hpd_irq_event(dp->drm_dev); + return IRQ_HANDLED; } static void analogix_dp_commit(struct analogix_dp_device *dp) @@ -1077,7 +1070,6 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge) } disable_irq(dp->irq); - flush_work(&dp->hotplug_work); phy_power_off(dp->phy); if (dp->plat_data->power_off) @@ -1336,8 +1328,6 @@ int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev, return -ENODEV; } - INIT_WORK(&dp->hotplug_work, analogix_dp_hotplug); - pm_runtime_enable(dev); phy_power_on(dp->phy); @@ -1351,8 +1341,10 @@ int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev, analogix_dp_init_dp(dp); - ret = devm_request_irq(&pdev->dev, dp->irq, analogix_dp_irq_handler, - irq_flags, "analogix-dp", dp); + ret = devm_request_threaded_irq(&pdev->dev, dp->irq, + analogix_dp_hardirq, + analogix_dp_irq_thread, + irq_flags, "analogix-dp", dp); if (ret) { dev_err(&pdev->dev, "failed to request irq\n"); goto err_disable_pm_runtime; diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h index 40a0759..a4e1330 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h @@ -172,7 +172,6 @@ struct analogix_dp_device { struct video_info video_info; struct link_train link_train; - struct work_struct hotplug_work; struct phy *phy; int dpms_mode; int hpd_gpio; @@ -191,6 +190,8 @@ void analogix_dp_init_interrupt(struct analogix_dp_device *dp); void analogix_dp_reset(struct analogix_dp_device *dp); void analogix_dp_swreset(struct analogix_dp_device *dp); void analogix_dp_config_interrupt(struct analogix_dp_device *dp); +void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp); +void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp); enum pll_status analogix_dp_get_pll_lock_status(struct analogix_dp_device *dp); void analogix_dp_set_pll_power_down(struct analogix_dp_device *dp, bool enable); void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp, diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c index 8687eea..928103e 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c @@ -185,6 +185,32 @@ void analogix_dp_config_interrupt(struct analogix_dp_device *dp) writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK); } +void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp) +{ + u32 reg; + + /* 0: mask, 1: unmask */ + reg = readl(dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4); + reg &= ~COMMON_INT_MASK_4; + writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4); + + reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA_MASK); + reg &= ~INT_STA_MASK; + writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK); +} + +void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp) +{ + u32 reg; + + /* 0: mask, 1: unmask */ + reg = COMMON_INT_MASK_4; + writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4); + + reg = INT_STA_MASK; + writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK); +} + enum pll_status analogix_dp_get_pll_lock_status(struct analogix_dp_device *dp) { u32 reg;