From patchwork Tue Oct 21 10:47:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5115611 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 512CAC11AC for ; Tue, 21 Oct 2014 11:19:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6D31D2010F for ; Tue, 21 Oct 2014 11:19:56 +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 8D25C200FE for ; Tue, 21 Oct 2014 11:19:55 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 54F23D8C; Tue, 21 Oct 2014 11:02:27 +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 7F97FD94 for ; Tue, 21 Oct 2014 11:02:26 +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 0E2281FAB2 for ; Tue, 21 Oct 2014 11:02:26 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 21 Oct 2014 04:02:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617794098" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:02:24 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:47:42 +0800 Message-Id: <1413889294-31328-263-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> MIME-Version: 1.0 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 0262/1094] Revert "drm/i915: enable HiZ Raw Stall Optimization on IVB" 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: , Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Chris Wilson This reverts commit 116f2b6da868dec7539103574d0421cd6221e931. This optimization causes widespread corruption in games, and even in glxgears, on my ivb:gt1. The corruption appears like z-fighting of overlapping polygons in the HiZ buffer. The observation ties in very closely with the description of the optimization disabled by default on IVB: "The Hierarchical Z RAW Stall Optimization allows non-overlapping polygons in the same 8x4 pixel/sample area to be processed without stalling waiting for the earlier ones to write to Hierarchical Z buffer." No reason is given for why it is disabled by default, usually for such optimizations it is that it is incomplete. However, there is no indication whether this a gt1 only issue either. Before considering reenabling this optimization, I would first suggest reproducing the corruption in piglit. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75623 Signed-off-by: Chris Wilson Cc: Chia-I Wu Cc: Ville Syrjälä Signed-off-by: Daniel Vetter (cherry picked from commit 227213438aff3050f2dd2be92dc48c8370d445a2) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/intel_pm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 6436b70..3855085 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4974,9 +4974,11 @@ static void ivybridge_init_clock_gating(struct drm_device *dev) gen7_setup_fixed_func_scheduler(dev_priv); - /* enable HiZ Raw Stall Optimization */ - I915_WRITE(CACHE_MODE_0_GEN7, - _MASKED_BIT_DISABLE(HIZ_RAW_STALL_OPT_DISABLE)); + if (0) { /* causes HiZ corruption on ivb:gt1 */ + /* enable HiZ Raw Stall Optimization */ + I915_WRITE(CACHE_MODE_0_GEN7, + _MASKED_BIT_DISABLE(HIZ_RAW_STALL_OPT_DISABLE)); + } /* WaDisable4x2SubspanOptimization:ivb */ I915_WRITE(CACHE_MODE_1,