From patchwork Thu Mar 14 15:52:05 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mika Kuoppala X-Patchwork-Id: 2272211 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork2.kernel.org (Postfix) with ESMTP id B72E5DFB79 for ; Thu, 14 Mar 2013 15:56:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AF36EE6969 for ; Thu, 14 Mar 2013 08:56:21 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id A93BFE6991 for ; Thu, 14 Mar 2013 08:49:15 -0700 (PDT) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP; 14 Mar 2013 08:49:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,845,1355126400"; d="scan'208";a="302178352" Received: from unknown (HELO rosetta) ([10.237.72.51]) by orsmga002.jf.intel.com with ESMTP; 14 Mar 2013 08:48:44 -0700 Received: by rosetta (Postfix, from userid 1000) id 3FB3D80096; Thu, 14 Mar 2013 17:52:22 +0200 (EET) From: Mika Kuoppala To: intel-gfx@lists.freedesktop.org Date: Thu, 14 Mar 2013 17:52:05 +0200 Message-Id: <1363276337-12509-5-git-send-email-mika.kuoppala@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1363276337-12509-1-git-send-email-mika.kuoppala@intel.com> References: <1363276337-12509-1-git-send-email-mika.kuoppala@intel.com> Cc: Daniel Vetter , Ben Widawsky , miku@iki.fi Subject: [Intel-gfx] [PATCH v2 04/16] drm/i915: Resurrect ring kicking for semaphores, selectively X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org From: Chris Wilson Once we thought we got semaphores working, we disabled kicking the ring if hangcheck fired whilst waiting upon a ring as it was doing more harm than good: commit 4e0e90dcb8a7df1229c69e30abebb59b0b3c2a1f Author: Daniel Vetter Date: Wed Dec 14 13:56:58 2011 +0100 drm/i915: kicking rings stuck on semaphores considered harmful However, life is never that easy and semaphores are still causing problems whereby the value written by one ring (bcs) is not being propagated to the waiter (rcs). Thus the waiter never wakes up and we declare the GPU hung, which often has unfortunate consequences, even if we successfully reset the GPU. But the GPU is idle as it has completed the work, just didn't notify its clients. So we can detect the incomplete wait during hang check and probe the target ring to see if has indeed emitted the breadcrumb seqno following the work and then and only then kick the waiter. Based on a suggestion by Ben Widawsky. v2: cross-check wait with iphdr. fix signaller calculation. References: https://bugs.freedesktop.org/show_bug.cgi?id=54226 Signed-off-by: Chris Wilson Signed-off-by: Mika Kuoppala Cc: Daniel Vetter Cc: Ben Widawsky Acked-by: Ben Widawsky --- drivers/gpu/drm/i915/i915_irq.c | 40 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 2139714..ce7efa8 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1787,6 +1787,37 @@ static bool i915_hangcheck_ring_idle(struct intel_ring_buffer *ring, bool *err) return false; } +static bool semaphore_passed(struct intel_ring_buffer *ring) +{ + struct drm_i915_private *dev_priv = ring->dev->dev_private; + u32 acthd = intel_ring_get_active_head(ring) & HEAD_ADDR; + struct intel_ring_buffer *signaller; + u32 cmd, ipehr, acthd_min; + + ipehr = I915_READ(RING_IPEHR(ring->mmio_base)); + if ((ipehr & ~(0x3 << 16)) != + (MI_SEMAPHORE_MBOX | MI_SEMAPHORE_COMPARE | MI_SEMAPHORE_REGISTER)) + return false; + + /* ACTHD is likely pointing to the dword after the actual command, + * so scan backwards until we find the MBOX. + */ + acthd_min = max((int)acthd - 3 * 4, 0); + do { + cmd = ioread32(ring->virtual_start + acthd); + if (cmd == ipehr) + break; + + acthd -= 4; + if (acthd < acthd_min) + return false; + } while (1); + + signaller = &dev_priv->ring[(ring->id + (((ipehr >> 17) & 1) + 1)) % 3]; + return i915_seqno_passed(signaller->get_seqno(signaller, false), + ioread32(ring->virtual_start+acthd+4)+1); +} + static bool kick_ring(struct intel_ring_buffer *ring) { struct drm_device *dev = ring->dev; @@ -1798,6 +1829,15 @@ static bool kick_ring(struct intel_ring_buffer *ring) I915_WRITE_CTL(ring, tmp); return true; } + + if (INTEL_INFO(dev)->gen >= 6 && + tmp & RING_WAIT_SEMAPHORE && + semaphore_passed(ring)) { + DRM_ERROR("Kicking stuck semaphore on %s\n", + ring->name); + I915_WRITE_CTL(ring, tmp); + return true; + } return false; }