From patchwork Fri Jan 22 01:56:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yakir Yang X-Patchwork-Id: 8087301 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id ABB2DBEEE5 for ; Fri, 22 Jan 2016 02:02:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A053C20456 for ; Fri, 22 Jan 2016 02:02:00 +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 895D420328 for ; Fri, 22 Jan 2016 02:01:59 +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 1aMR1P-0001xc-Qz; Fri, 22 Jan 2016 02:00:19 +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 1aMQyL-0006y9-1T; Fri, 22 Jan 2016 01:57:14 +0000 Received: from ykk?rock-chips.com (unknown [192.168.167.129]) by lucky1.263xmail.com (Postfix) with SMTP id 8B1204E7B6; Fri, 22 Jan 2016 09:56:47 +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 4E31D12822; Fri, 22 Jan 2016 09:56:38 +0800 (CST) X-RL-SENDER: ykk@rock-chips.com X-FST-TO: inki.dae@samsung.com X-SENDER-IP: 103.29.142.67 X-LOGIN-NAME: ykk@rock-chips.com X-UNIQUE-TAG: <523583d23014b031dbe1c2571148fd0a> X-ATTACHMENT-NUM: 0 X-SENDER: ykk@rock-chips.com X-DNS-TYPE: 0 Received: from localhost.localdomain (unknown [103.29.142.67]) by smtp.263.net (Postfix) whith ESMTP id 101444U6650; Fri, 22 Jan 2016 09:56:42 +0800 (CST) From: Yakir Yang To: Inki Dae , Kyungmin Park , Jingoo Han , Thierry Reding , Krzysztof Kozlowski , Rob Herring , Heiko Stuebner , Mark Yao Subject: [PATCH v13 17/17] drm: bridge: analogix/dp: Fix the possible dead lock in bridge disable time Date: Fri, 22 Jan 2016 09:56:42 +0800 Message-Id: <1453427802-24787-1-git-send-email-ykk@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1453427614-23053-1-git-send-email-ykk@rock-chips.com> References: <1453427614-23053-1-git-send-email-ykk@rock-chips.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160121_175709_858364_8E019F02 X-CRM114-Status: GOOD ( 14.33 ) 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, 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, Yakir Yang , Andy Yan , 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 v13: None 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 5292b28..7699597 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 cba3ffd..49205ef 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;