From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8558EC433EF for ; Mon, 20 Sep 2021 07:42:57 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 493B360F26 for ; Mon, 20 Sep 2021 07:42:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 493B360F26 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A38816E409; Mon, 20 Sep 2021 07:42:56 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id B3F606E409; Mon, 20 Sep 2021 07:42:54 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10112"; a="223126189" X-IronPort-AV: E=Sophos;i="5.85,307,1624345200"; d="scan'208";a="223126189" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Sep 2021 00:42:47 -0700 X-IronPort-AV: E=Sophos;i="5.85,307,1624345200"; d="scan'208";a="473462349" Received: from gbradyx-mobl2.ger.corp.intel.com (HELO [10.213.235.119]) ([10.213.235.119]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Sep 2021 00:42:45 -0700 To: Jani Nikula , Matthew Brost , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: Hugh Dickins References: <20210917233818.33659-1-matthew.brost@intel.com> <8c906ac4-c6a3-ee45-970f-07679456fd18@linux.intel.com> <87fstzvgrr.fsf@intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <5fbbf1dc-e5fa-263c-ab2a-f308fae035f6@linux.intel.com> Date: Mon, 20 Sep 2021 08:42:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <87fstzvgrr.fsf@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Intel-gfx] [PATCH] drm/i915: fix blank screen booting crashes X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 20/09/2021 08:38, Jani Nikula wrote: > On Mon, 20 Sep 2021, Tvrtko Ursulin wrote: >> On 18/09/2021 00:38, Matthew Brost wrote: >>> From: Hugh Dickins >>> >>> 5.15-rc1 crashes with blank screen when booting up on two ThinkPads >>> using i915. Bisections converge convincingly, but arrive at different >>> and surprising "culprits", none of them the actual culprit. >> >> It is certainly surprising this patch crashed SNB and KBL. >> >> How feasible would it be to make this code just not run when GuC is not >> used? Given the field it adds is called ce->guc_blocked it sounds like a >> natural and preferable thing to do... if possible. >> >>> netconsole (with init_netconsole() hacked to call i915_init() when >>> logging has started, instead of by module_init()) tells the story: >>> >>> kernel BUG at drivers/gpu/drm/i915/i915_sw_fence.c:245! >>> with RSI: ffffffff814d408b pointing to sw_fence_dummy_notify(). >>> I've been building with CONFIG_CC_OPTIMIZE_FOR_SIZE=y, and that >>> function needs to be 4-byte aligned. >>> >>> v2: >>> (Jani Nikula) >>> - Change BUG_ON to WARN_ON >> >> However in this case the code would then go on and call into a wrong >> function offset which may be worse than a BUG_ON, no? > > So how about just > > if (WARN_ON(...)) > return; > > or whatever is needed to give both the user and the CI a better > opportunity to see the error. Sounds good to me. Regards, Tvrtko > > BR, > Jani > > >> >>> >>> Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") >>> Signed-off-by: Hugh Dickins >>> Signed-off-by: Matthew Brost >>> Reviewed-by: Matthew Brost >>> --- >>> drivers/gpu/drm/i915/gt/intel_context.c | 1 + >>> drivers/gpu/drm/i915/i915_sw_fence.c | 4 +++- >>> 2 files changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c >>> index ff637147b1a9..f02c2202da9d 100644 >>> --- a/drivers/gpu/drm/i915/gt/intel_context.c >>> +++ b/drivers/gpu/drm/i915/gt/intel_context.c >>> @@ -362,6 +362,7 @@ static int __intel_context_active(struct i915_active *active) >>> return 0; >>> } >>> >>> +__aligned(4) /* Respect the I915_SW_FENCE_MASK */ >> >> Hugh suggested __i915_sw_fence_call which I think would be the right >> thing to do. >> >> Regards, >> >> Tvrtko >> >>> static int sw_fence_dummy_notify(struct i915_sw_fence *sf, >>> enum i915_sw_fence_notify state) >>> { >>> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c >>> index c589a681da77..1217b124c1d0 100644 >>> --- a/drivers/gpu/drm/i915/i915_sw_fence.c >>> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c >>> @@ -14,8 +14,10 @@ >>> >>> #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) >>> #define I915_SW_FENCE_BUG_ON(expr) BUG_ON(expr) >>> +#define I915_SW_FENCE_WARN_ON(expr) WARN_ON(expr) >>> #else >>> #define I915_SW_FENCE_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) >>> +#define I915_SW_FENCE_WARN_ON(expr) BUILD_BUG_ON_INVALID(expr) >>> #endif >>> >>> static DEFINE_SPINLOCK(i915_sw_fence_lock); >>> @@ -242,7 +244,7 @@ void __i915_sw_fence_init(struct i915_sw_fence *fence, >>> const char *name, >>> struct lock_class_key *key) >>> { >>> - BUG_ON(!fn || (unsigned long)fn & ~I915_SW_FENCE_MASK); >>> + I915_SW_FENCE_WARN_ON(!fn || (unsigned long)fn & ~I915_SW_FENCE_MASK); >>> >>> __init_waitqueue_head(&fence->wait, name, key); >>> fence->flags = (unsigned long)fn; >>> >