From patchwork Sun Jan 17 11:04:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 12025311 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 AB7BCC433E0 for ; Sun, 17 Jan 2021 11:04:34 +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 F03BE227BF for ; Sun, 17 Jan 2021 11:04:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F03BE227BF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7C46B89F49; Sun, 17 Jan 2021 11:04:33 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2F6B389F49 for ; Sun, 17 Jan 2021 11:04:31 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 23620485-1500050 for multiple; Sun, 17 Jan 2021 11:04:19 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Sun, 17 Jan 2021 11:04:18 +0000 Message-Id: <20210117110418.3361-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/gt: Add arbitration check before semaphore wait 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: , Cc: Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Similar to commit 49b20dbf7497 ("drm/i915/gt: Perform an arbitration check before busywaiting"), also add a check prior to the busywait on gen8+, as we have now seen (because we added a selftest to add fault injection into the engine resets) the same engine reset failure leading to an indefinite wait on the ring-stop semaphore. So not a Tigerlake specific bug after all, though it still seems odd behaviour for the busywait as we do get the arbitration point elsewhere on a miss. Testcase: igt_reset_fail_engine Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/gt/gen8_engine_cs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c index 5b932d2dbfd3..07ba524da90b 100644 --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c @@ -488,6 +488,7 @@ static u32 *gen8_emit_wa_tail(struct i915_request *rq, u32 *cs) static u32 *emit_preempt_busywait(struct i915_request *rq, u32 *cs) { + *cs++ = MI_ARB_CHECK; /* trigger IDLE->ACTIVE first */ *cs++ = MI_SEMAPHORE_WAIT | MI_SEMAPHORE_GLOBAL_GTT | MI_SEMAPHORE_POLL | @@ -495,6 +496,7 @@ static u32 *emit_preempt_busywait(struct i915_request *rq, u32 *cs) *cs++ = 0; *cs++ = preempt_address(rq->engine); *cs++ = 0; + *cs++ = MI_NOOP; return cs; }