From patchwork Mon Nov 18 16:23:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11249947 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0A4DE930 for ; Mon, 18 Nov 2019 16:24:07 +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 9F33020885 for ; Mon, 18 Nov 2019 16:24:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F33020885 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 5FF9589CA0; Mon, 18 Nov 2019 16:24:05 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1061C89CA0 for ; Mon, 18 Nov 2019 16:24:03 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 19244584-1500050 for multiple; Mon, 18 Nov 2019 16:23:43 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Mon, 18 Nov 2019 16:23:42 +0000 Message-Id: <20191118162342.2452211-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/gt: Unlock engine-pm after queuing the kernel context switch X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 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" In commit a79ca656b648 ("drm/i915: Push the wakeref->count deferral to the backend"), I erroneously concluded that we last modify the engine inside __i915_request_commit() meaning that we could enable concurrent submission for userspace as we enqueued this request. However, this falls into a trap with other users of the engine->kernel_context waking up and submitting their request before the idle-switch is queued, with the result that the kernel_context is executed out-of-sequence most likely upsetting the GPU and certainly ourselves when we try to retire the out-of-sequence requests. As such we need to hold onto the effective engine->kernel_context mutex lock (via the engine pm mutex proxy) until we have finish queuing the request to the engine. Fixes: a79ca656b648 ("drm/i915: Push the wakeref->count deferral to the backend") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Tvrtko Ursulin --- drivers/gpu/drm/i915/gt/intel_engine_pm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c index 3c0f490ff2c7..2d2a21752ae4 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -116,11 +116,12 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine) rq->sched.attr.priority = I915_PRIORITY_BARRIER; __i915_request_commit(rq); - /* Release our exclusive hold on the engine */ - __intel_wakeref_defer_park(&engine->wakeref); __i915_request_queue(rq, NULL); + /* Release our exclusive hold on the engine */ + __intel_wakeref_defer_park(&engine->wakeref); result = false; + out_unlock: __timeline_mark_unlock(engine->kernel_context, flags); return result;