From patchwork Wed Mar 9 11:52:53 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 8545811 Return-Path: X-Original-To: patchwork-intel-gfx@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 938ECC0553 for ; Wed, 9 Mar 2016 11:51:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 842A320263 for ; Wed, 9 Mar 2016 11:51:52 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 1915420254 for ; Wed, 9 Mar 2016 11:51:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 67B2B6E0D3; Wed, 9 Mar 2016 11:51:47 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mailout3.hostsharing.net (mailout3.hostsharing.net [176.9.242.54]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6396A6E0D3 for ; Wed, 9 Mar 2016 11:51:45 +0000 (UTC) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout3.hostsharing.net (Postfix) with ESMTPS id E52A2101E69A2; Wed, 9 Mar 2016 12:51:43 +0100 (CET) Received: from localhost (6-38-90-81.adsl.cmo.de [81.90.38.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 5583E60049B6; Wed, 9 Mar 2016 12:51:42 +0100 (CET) X-Mailbox-Line: From 7a3ad38b3a01a2936db8d8604d546b9927052f9a Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Wed, 9 Mar 2016 12:52:53 +0100 MIME-Version: 1.0 X-Mailer: git-send-email 2.4.3 To: intel-gfx@lists.freedesktop.org Cc: Gustav Fagerlind , "Li, Weinan Z" Subject: [Intel-gfx] [PATCH v2] drm/i915: Fix races on fbdev X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Message-Id: <20160309115147.67B2B6E0D3@gabe.freedesktop.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 The ->lastclose callback invokes intel_fbdev_restore_mode() and has been witnessed to run before intel_fbdev_initial_config_async() has finished. We might likewise receive hotplug events before we've had a chance to fully set up the fbdev. Fix by waiting for the asynchronous thread to finish. v2: An async_synchronize_full() was also added to intel_fbdev_set_suspend() in v1 which turned out to be entirely gratuitous. It caused a deadlock on suspend (discovered by CI, thanks to Damien Lespiau and Tomi Sarvela for CI support) and was unnecessary since a device is never suspended until its ->probe callback (and all asynchronous tasks it scheduled) have finished. See dpm_prepare(), which calls wait_for_device_probe(), which calls async_synchronize_full(). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93580 Reported-by: Gustav Fägerlind Reported-by: "Li, Weinan Z" Cc: Chris Wilson Cc: stable@vger.kernel.org Signed-off-by: Lukas Wunner --- drivers/gpu/drm/i915/i915_dma.c | 8 +++----- drivers/gpu/drm/i915/intel_fbdev.c | 3 +++ 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 4aa3db6..9d76dfb 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -430,11 +430,9 @@ static int i915_load_modeset_init(struct drm_device *dev) * Some ports require correctly set-up hpd registers for detection to * work properly (leading to ghost connected connector status), e.g. VGA * on gm45. Hence we can only set up the initial fbdev config after hpd - * irqs are fully enabled. Now we should scan for the initial config - * only once hotplug handling is enabled, but due to screwed-up locking - * around kms/fbdev init we can't protect the fdbev initial config - * scanning against hotplug events. Hence do this first and ignore the - * tiny window where we will loose hotplug notifactions. + * irqs are fully enabled. We protect the fbdev initial config scanning + * against hotplug events by waiting in intel_fbdev_output_poll_changed + * until the asynchronous thread has finished. */ intel_fbdev_initial_config_async(dev); diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c index ae9cf6f..7e73acc 100644 --- a/drivers/gpu/drm/i915/intel_fbdev.c +++ b/drivers/gpu/drm/i915/intel_fbdev.c @@ -800,6 +800,8 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous void intel_fbdev_output_poll_changed(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; + + async_synchronize_full(); if (dev_priv->fbdev) drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper); } @@ -811,6 +813,7 @@ void intel_fbdev_restore_mode(struct drm_device *dev) struct intel_fbdev *ifbdev = dev_priv->fbdev; struct drm_fb_helper *fb_helper; + async_synchronize_full(); if (!ifbdev) return;