From patchwork Tue Oct 21 10:44:11 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5113241 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 91BEA9F43D for ; Tue, 21 Oct 2014 11:01:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C001A20148 for ; Tue, 21 Oct 2014 11:01:18 +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 420B32012F for ; Tue, 21 Oct 2014 11:01:17 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id CBC1AB37; Tue, 21 Oct 2014 10:58:25 +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 0D746BB4 for ; Tue, 21 Oct 2014 10:58:24 +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 A7D962010C for ; Tue, 21 Oct 2014 10:58:23 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 21 Oct 2014 03:58:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617791508" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 03:58:22 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:44:11 +0800 Message-Id: <1413889294-31328-52-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 0051/1094] drm/i915: set ctx->initialized only after RCS 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: Ben Widawsky The initialized flag is used to specify a context has been initialized and it's context is safe to load, ie. the 3d state is setup properly. With full PPGTT, we emit the address space loads during context switch and this currently marks a context as initialized. With full PPGTT patches, if a client first emits a batch to !RCS, then later, RCS, the code will mistake the context as initialized and try to reload an uninitialized context. 1. context 1 blit // context marked as initialized, but isn't 2. context 1 render // loads random state from step 2 It is really easy to hit this with a planned upcoming patch which makes default context reuse possible. NOTE: This should only effect full PPGTT branches, ie. current drm-intel-nightly. Thanks to Chris for helping me track this down. Cc: Chris Wilson Signed-off-by: Ben Widawsky Reviewed-by: Chris Wilson [danvet: Simplify the failure scenario in the commit message according to Chris' review a bit.] Signed-off-by: Daniel Vetter (cherry picked from commit ad1d219974a3d13412268525309c5892f6779ae9) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/i915_gem_context.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index ae8bbca..8d86461 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -692,10 +692,11 @@ static int do_switch(struct intel_ring_buffer *ring, i915_gem_context_unreference(from); } + to->is_initialized = true; + done: i915_gem_context_reference(to); ring->last_context = to; - to->is_initialized = true; to->last_ring = ring; return 0;