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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 99AA3C388F9 for ; Tue, 3 Nov 2020 14:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B58422243 for ; Tue, 3 Nov 2020 14:16:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729637AbgKCOQ5 convert rfc822-to-8bit (ORCPT ); Tue, 3 Nov 2020 09:16:57 -0500 Received: from mail.fireflyinternet.com ([77.68.26.236]:64681 "EHLO fireflyinternet.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729636AbgKCOQS (ORCPT ); Tue, 3 Nov 2020 09:16:18 -0500 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 22881066-1500050 for multiple; Tue, 03 Nov 2020 14:16:03 +0000 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT In-Reply-To: <87361qfw3e.fsf@gaia.fi.intel.com> References: <20201102221057.29626-1-chris@chris-wilson.co.uk> <20201102221057.29626-2-chris@chris-wilson.co.uk> <87361qfw3e.fsf@gaia.fi.intel.com> Subject: Re: [PATCH 2/2] drm/i915/gt: Flush xcs before tgl breadcrumbs From: Chris Wilson Cc: stable@vger.kernel.org To: Mika Kuoppala , intel-gfx@lists.freedesktop.org Date: Tue, 03 Nov 2020 14:16:00 +0000 Message-ID: <160441296035.21466.9227014206344926879@build.alporthouse.com> User-Agent: alot/0.9 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Quoting Mika Kuoppala (2020-11-03 12:44:53) > Chris Wilson writes: > > > In a simple test case that writes to scratch and then busy-waits for the > > batch to be signaled, we observe that the signal is before the write is > > posted. That is bad news. > > > > Splitting the flush + write_dword into two separate flush_dw prevents > > the issue from being reproduced, we can presume the post-sync op is not > > so post-sync. > > > > Only thing that is mildly surpricing is that first one doesnt > need postop write. The MI_FLUSH_DW is stalling, so the second will^W should wait for the first to complete. (And we don't want to do the write from the first as we observe that write is too early.) -Chris 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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 5F290C2D0A3 for ; Tue, 3 Nov 2020 14:16:07 +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 63A2622226 for ; Tue, 3 Nov 2020 14:16:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63A2622226 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 0428F6ECB2; Tue, 3 Nov 2020 14:16:06 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7DD106ECB2 for ; Tue, 3 Nov 2020 14:16:04 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 22881066-1500050 for multiple; Tue, 03 Nov 2020 14:16:03 +0000 MIME-Version: 1.0 In-Reply-To: <87361qfw3e.fsf@gaia.fi.intel.com> References: <20201102221057.29626-1-chris@chris-wilson.co.uk> <20201102221057.29626-2-chris@chris-wilson.co.uk> <87361qfw3e.fsf@gaia.fi.intel.com> From: Chris Wilson To: Mika Kuoppala , intel-gfx@lists.freedesktop.org Date: Tue, 03 Nov 2020 14:16:00 +0000 Message-ID: <160441296035.21466.9227014206344926879@build.alporthouse.com> User-Agent: alot/0.9 Subject: Re: [Intel-gfx] [PATCH 2/2] drm/i915/gt: Flush xcs before tgl breadcrumbs 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: stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Mika Kuoppala (2020-11-03 12:44:53) > Chris Wilson writes: > > > In a simple test case that writes to scratch and then busy-waits for the > > batch to be signaled, we observe that the signal is before the write is > > posted. That is bad news. > > > > Splitting the flush + write_dword into two separate flush_dw prevents > > the issue from being reproduced, we can presume the post-sync op is not > > so post-sync. > > > > Only thing that is mildly surpricing is that first one doesnt > need postop write. The MI_FLUSH_DW is stalling, so the second will^W should wait for the first to complete. (And we don't want to do the write from the first as we observe that write is too early.) -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx