From patchwork Tue Oct 21 10:48:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5116251 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 94208C11AC for ; Tue, 21 Oct 2014 11:24:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 919F92010F for ; Tue, 21 Oct 2014 11:24:42 +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 6B335200CA for ; Tue, 21 Oct 2014 11:24:41 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 7DE24BF9; Tue, 21 Oct 2014 11:03:43 +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 30F22E20 for ; Tue, 21 Oct 2014 11:03:40 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 720E61FFFA for ; Tue, 21 Oct 2014 11:03:39 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:03:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617794900" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:03:38 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:48:42 +0800 Message-Id: <1413889294-31328-323-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 0322/1094] drm/i915: Disable full ppgtt by default 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: Daniel Vetter There are too many oustanding issues: - Fence handling in the current code is broken. There's a patch series from me, but it's blocked on and extended review (which includes writing the testcases). - IOMMU mapping handling is broken, we need to properly refcount it - currently it gets destroyed when the first vma is unbound, so way too early. - There's a pending reset issue on snb. Since Mika's reset work and full ppgtt have been pulled in in separate branches and ended up intermittingly breaking each another it's unclear who's the exact culprit here. - We still have persistent evidince of crazy recursion bugs through vma_unbind and ppgtt_relase, e.g. https://bugs.freedesktop.org/show_bug.cgi?id=73383 This issue (and a few others meanwhile resolved) have blocked our performance measuring/tuning group since 3 months. - Secure batch dispatching is broken. This is blocking Brad Volkin's command checker work since 3 months. All these issues are confirmed to only happen when full ppgtt is enabled, falling back to aliasing ppgtt resolves them. But even aliasing ppgtt itself still has a regression: - We currently unconditionally bind objects into the aliasing ppgtt, which means all priviledged objects like ringbuffers are visible to unpriviledged access again. On top of that this also breaks the command checker for aliasing ppgtt, since it can't hide the validated batch any more. Furthermore topic/full-ppgtt has never been reviewed: - Lifetime rules around vma unbinding/release are unclear, resulting into this awesome hack called ppgtt_release. Which seems to take the blame for most of the recursion fallout. - Context/ring init works different on gpu reset than anywhere else. Such differeneces have in the past always lead to really hard to track down bugs. - Aliasing ppgtt is treated in a bunch of places as a real address space, but it isn't - the real address space is always the global gtt in that case. This results in a bit a mess between contexts and ppgtt object, further complication the context/ppgtt/vma lifetime rules. - We don't have any docs describing the overall concepts introduced with full ppgtt. A short, concise overview describing vmas and some of the strange bits around them (like the unbound vmas used by execbuf, or the new binding rules) really is needed. Note that a lot of the post topic/full-ppgtt merge fallout has already been addressed, this entire list here of 10 issues really only contains the still outstanding issues. Finally the 3.15 merge window is approaching and I think we need to use the remaining time to ensure that our fallback option of using aliasing ppgtt is in solid shape. Hence I think it's time to throw the switch. While at it demote the helper from static inline status because really. Cc: Ben Widawsky Cc: Dave Airlie Signed-off-by: Daniel Vetter (cherry picked from commit 93a25a9e2d67765c3092bfaac9b855d95e39df97) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/i915_drv.h | 22 +--------------------- drivers/gpu/drm/i915/i915_gem_gtt.c | 23 +++++++++++++++++++++++ 2 files changed, 24 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 9609f83..29da39f 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2385,27 +2385,7 @@ static inline void i915_gem_chipset_flush(struct drm_device *dev) intel_gtt_chipset_flush(); } int i915_gem_init_ppgtt(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt); -static inline bool intel_enable_ppgtt(struct drm_device *dev, bool full) -{ - if (i915.enable_ppgtt == 0 || !HAS_ALIASING_PPGTT(dev)) - return false; - - if (i915.enable_ppgtt == 1 && full) - return false; - -#ifdef CONFIG_INTEL_IOMMU - /* Disable ppgtt on SNB if VT-d is on. */ - if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped) { - DRM_INFO("Disabling PPGTT because VT-d is on\n"); - return false; - } -#endif - - if (full) - return HAS_PPGTT(dev); - else - return HAS_ALIASING_PPGTT(dev); -} +bool intel_enable_ppgtt(struct drm_device *dev, bool full); /* i915_gem_stolen.c */ int i915_gem_init_stolen(struct drm_device *dev); diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 457c78a..d4117ba 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -30,6 +30,29 @@ #include "i915_trace.h" #include "intel_drv.h" +bool intel_enable_ppgtt(struct drm_device *dev, bool full) +{ + if (i915.enable_ppgtt == 0 || !HAS_ALIASING_PPGTT(dev)) + return false; + + if (i915.enable_ppgtt == 1 && full) + return false; + +#ifdef CONFIG_INTEL_IOMMU + /* Disable ppgtt on SNB if VT-d is on. */ + if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped) { + DRM_INFO("Disabling PPGTT because VT-d is on\n"); + return false; + } +#endif + + /* Full ppgtt disabled by default for now due to issues. */ + if (full) + return false; /* HAS_PPGTT(dev) */ + else + return HAS_ALIASING_PPGTT(dev); +} + #define GEN6_PPGTT_PD_ENTRIES 512 #define I915_PPGTT_PT_ENTRIES (PAGE_SIZE / sizeof(gen6_gtt_pte_t)) typedef uint64_t gen8_gtt_pte_t;