From patchwork Sat Aug 8 16:04:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 6975281 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 5ECC0C05AC for ; Sat, 8 Aug 2015 16:11:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6BFA9205FE for ; Sat, 8 Aug 2015 16:11:47 +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 93C162053C for ; Sat, 8 Aug 2015 16:11:46 +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 1ZO6gp-0001lQ-Mc; Sat, 08 Aug 2015 16:09:43 +0000 Received: from pandora.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZO6eX-0007UV-J0 for linux-arm-kernel@lists.infradead.org; Sat, 08 Aug 2015 16:07:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora-2014; h=Date:Sender:Message-Id:Content-Type:Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References:In-Reply-To; bh=JDjCU5K23DMeG8ZkyLga10Xt25S/cyhGZSNg0GbU/EM=; b=qVXgaVuTWmBheEDNG+OkC700EX4FLBVYfKZi70JsNfbqrbylQhPSzwitUnih5zoQevIB21uN0yNG1au0Q3SxKO8TZkViKDGb0j+7S8bbqGTlL+IecoxhUcmGBOWXjmVx+LB8zEMVLkSa8WCAXWW7B0Hba9BVERCMmg/+bHRMWiw=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([2001:4d48:ad52:3201:222:68ff:fe15:37dd]:60370 helo=rmk-PC.arm.linux.org.uk) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZO6bf-0006MF-FY; Sat, 08 Aug 2015 17:04:23 +0100 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZO6bT-0002vk-3d; Sat, 08 Aug 2015 17:04:11 +0100 In-Reply-To: <20150808160251.GM7557@n2100.arm.linux.org.uk> References: <20150808160251.GM7557@n2100.arm.linux.org.uk> From: Russell King To: linux-rockchip@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 10/12] drm: bridge/dw_hdmi: fix phy enable/disable handling MIME-Version: 1.0 Content-Disposition: inline Message-Id: Date: Sat, 08 Aug 2015 17:04:11 +0100 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150808_090722_629227_869AD271 X-CRM114-Status: GOOD ( 13.64 ) X-Spam-Score: -2.4 (--) 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: Fabio Estevam , David Airlie , Sascha Hauer , Philipp Zabel , Yakir Yang , Andy Yan , Jon Nettleton Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,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 The dw_hdmi enable/disable handling is particularly weak in several regards: * The hotplug interrupt could call hdmi_poweron() or hdmi_poweroff() while DRM is setting a mode, which could race with a mode being set. * Hotplug will always re-enable the phy whenever it detects an active hotplug signal, even if DRM has disabled the output. Resolve all of these by introducing a mutex to prevent races, and a state-tracking bool so we know whether DRM wishes the output to be enabled. We choose to use our own mutex rather than ->struct_mutex so that we can still process interrupts in a timely fashion. Signed-off-by: Russell King --- drivers/gpu/drm/bridge/dw_hdmi.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c index 7b8a4e942a71..0ee188930d26 100644 --- a/drivers/gpu/drm/bridge/dw_hdmi.c +++ b/drivers/gpu/drm/bridge/dw_hdmi.c @@ -125,6 +125,9 @@ struct dw_hdmi { bool sink_is_hdmi; bool sink_has_audio; + struct mutex mutex; /* for state below and previous_mode */ + bool disabled; /* DRM has disabled our bridge */ + spinlock_t audio_lock; struct mutex audio_mutex; unsigned int sample_rate; @@ -1389,8 +1392,12 @@ static void dw_hdmi_bridge_mode_set(struct drm_bridge *bridge, { struct dw_hdmi *hdmi = bridge->driver_private; + mutex_lock(&hdmi->mutex); + /* Store the display mode for plugin/DKMS poweron events */ memcpy(&hdmi->previous_mode, mode, sizeof(hdmi->previous_mode)); + + mutex_unlock(&hdmi->mutex); } static bool dw_hdmi_bridge_mode_fixup(struct drm_bridge *bridge, @@ -1404,14 +1411,20 @@ static void dw_hdmi_bridge_disable(struct drm_bridge *bridge) { struct dw_hdmi *hdmi = bridge->driver_private; + mutex_lock(&hdmi->mutex); + hdmi->disabled = true; dw_hdmi_poweroff(hdmi); + mutex_unlock(&hdmi->mutex); } static void dw_hdmi_bridge_enable(struct drm_bridge *bridge) { struct dw_hdmi *hdmi = bridge->driver_private; + mutex_lock(&hdmi->mutex); dw_hdmi_poweron(hdmi); + hdmi->disabled = false; + mutex_unlock(&hdmi->mutex); } static void dw_hdmi_bridge_nop(struct drm_bridge *bridge) @@ -1534,20 +1547,20 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) phy_int_pol = hdmi_readb(hdmi, HDMI_PHY_POL0); if (intr_stat & HDMI_IH_PHY_STAT0_HPD) { + hdmi_modb(hdmi, ~phy_int_pol, HDMI_PHY_HPD, HDMI_PHY_POL0); + mutex_lock(&hdmi->mutex); if (phy_int_pol & HDMI_PHY_HPD) { dev_dbg(hdmi->dev, "EVENT=plugin\n"); - hdmi_modb(hdmi, 0, HDMI_PHY_HPD, HDMI_PHY_POL0); - - dw_hdmi_poweron(hdmi); + if (!hdmi->disabled) + dw_hdmi_poweron(hdmi); } else { dev_dbg(hdmi->dev, "EVENT=plugout\n"); - hdmi_modb(hdmi, HDMI_PHY_HPD, HDMI_PHY_HPD, - HDMI_PHY_POL0); - - dw_hdmi_poweroff(hdmi); + if (!hdmi->disabled) + dw_hdmi_poweroff(hdmi); } + mutex_unlock(&hdmi->mutex); drm_helper_hpd_irq_event(hdmi->bridge->dev); } @@ -1617,7 +1630,9 @@ int dw_hdmi_bind(struct device *dev, struct device *master, hdmi->sample_rate = 48000; hdmi->ratio = 100; hdmi->encoder = encoder; + hdmi->disabled = true; + mutex_init(&hdmi->mutex); mutex_init(&hdmi->audio_mutex); spin_lock_init(&hdmi->audio_lock);