From patchwork Tue Oct 21 11:00:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5124151 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DB49FC11AC for ; Tue, 21 Oct 2014 12:18:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F3CD7200E9 for ; Tue, 21 Oct 2014 12:18:50 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 166C5200E3 for ; Tue, 21 Oct 2014 12:18:50 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id B727E1684; Tue, 21 Oct 2014 11:17:19 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id ACB3E1642 for ; Tue, 21 Oct 2014 11:17:09 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 4350D1FB50 for ; Tue, 21 Oct 2014 11:17:09 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 21 Oct 2014 04:17:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617802672" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:17:07 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 19:00:52 +0800 Message-Id: <1413889294-31328-1053-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> X-Spam-Status: No, score=-5.6 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 Subject: [LTSI-dev] [PATCH 1052/1094] drm/i915: Reorder semaphore deadlock check X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Chris Wilson If a semaphore is waiting on another ring, which in turn happens to be waiting on the first ring, but that second semaphore has been signalled, we will be able to kick the second ring and so can treat the first ring as a valid WAIT and not as HUNG. v2: Be paranoid and cap the potential recursion depth whilst visiting the semaphore signallers. (Mika) References: https://bugs.freedesktop.org/show_bug.cgi?id=54226 References: https://bugs.freedesktop.org/show_bug.cgi?id=75502 Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: stable@vger.kernel.org Reviewed-by: Mika Kuoppala Signed-off-by: Jani Nikula (cherry picked from commit 4be173813e57c7298103a83155c2391b5b167b4c) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/i915_irq.c | 18 ++++++++++++++---- drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index cf288a9..69aaa11 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -2847,10 +2847,14 @@ static int semaphore_passed(struct intel_engine_cs *ring) struct intel_engine_cs *signaller; u32 seqno, ctl; - ring->hangcheck.deadlock = true; + ring->hangcheck.deadlock++; signaller = semaphore_waits_for(ring, &seqno); - if (signaller == NULL || signaller->hangcheck.deadlock) + if (signaller == NULL) + return -1; + + /* Prevent pathological recursion due to driver bugs */ + if (signaller->hangcheck.deadlock >= I915_NUM_RINGS) return -1; /* cursory check for an unkickable deadlock */ @@ -2858,7 +2862,13 @@ static int semaphore_passed(struct intel_engine_cs *ring) if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0) return -1; - return i915_seqno_passed(signaller->get_seqno(signaller, false), seqno); + if (i915_seqno_passed(signaller->get_seqno(signaller, false), seqno)) + return 1; + + if (signaller->hangcheck.deadlock) + return -1; + + return 0; } static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv) @@ -2867,7 +2877,7 @@ static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv) int i; for_each_ring(ring, dev_priv, i) - ring->hangcheck.deadlock = false; + ring->hangcheck.deadlock = 0; } static enum intel_ring_hangcheck_action diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 910c83c..e72017b 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -55,7 +55,7 @@ struct intel_ring_hangcheck { u32 seqno; int score; enum intel_ring_hangcheck_action action; - bool deadlock; + int deadlock; }; struct intel_ringbuffer {