From patchwork Wed Dec 16 04:01:51 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yakir Yang X-Patchwork-Id: 7859831 Return-Path: X-Original-To: patchwork-linux-samsung-soc@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 95DB9BEEE5 for ; Wed, 16 Dec 2015 04:04:04 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7C434203B8 for ; Wed, 16 Dec 2015 04:04:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF6C2202F8 for ; Wed, 16 Dec 2015 04:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932583AbbLPEEA (ORCPT ); Tue, 15 Dec 2015 23:04:00 -0500 Received: from lucky1.263xmail.com ([211.157.147.133]:44604 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753605AbbLPED7 (ORCPT ); Tue, 15 Dec 2015 23:03:59 -0500 Received: from ykk?rock-chips.com (unknown [192.168.167.234]) by lucky1.263xmail.com (Postfix) with SMTP id C93EB4EAE3; Wed, 16 Dec 2015 12:03:55 +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 E870C45A; Wed, 16 Dec 2015 12:03:53 +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: <3bd19d0cda25b433a1588c93cc642f86> 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 22786CJDBWE; Wed, 16 Dec 2015 12:03:56 +0800 (CST) From: Yakir Yang To: Inki Dae , Mark Yao , Jingoo Han , Heiko Stuebner Cc: Thierry Reding , Krzysztof Kozlowski , Rob Herring , Russell King , emil.l.velikov@gmail.com, Gustavo Padovan , Kishon Vijay Abraham I , javier@osg.samsung.com, Andy Yan , Yakir Yang , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v11 19/19] drm: bridge: analogix/dp: Fix the possible dead lock in bridge disable time Date: Wed, 16 Dec 2015 12:01:51 +0800 Message-Id: <1450238511-3414-1-git-send-email-ykk@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450236018-1118-1-git-send-email-ykk@rock-chips.com> References: <1450236018-1118-1-git-send-email-ykk@rock-chips.com> Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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 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 bc4a9e0..c66c522 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -848,47 +848,40 @@ 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) @@ -1034,7 +1027,6 @@ 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) @@ -1293,8 +1285,6 @@ 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); @@ -1308,8 +1298,10 @@ 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 73b780e..641f79d 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h @@ -178,7 +178,6 @@ 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; @@ -197,6 +196,8 @@ 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 dc376bd..00ac13c 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;