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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 86254CA9EC0 for ; Mon, 28 Oct 2019 22:51:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51AF821479 for ; Mon, 28 Oct 2019 22:51:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730286AbfJ1Wv5 (ORCPT ); Mon, 28 Oct 2019 18:51:57 -0400 Received: from foss.arm.com ([217.140.110.172]:46132 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725867AbfJ1Wv5 (ORCPT ); Mon, 28 Oct 2019 18:51:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6C8621F1; Mon, 28 Oct 2019 15:51:56 -0700 (PDT) Received: from [192.168.1.124] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 324343F6C4; Mon, 28 Oct 2019 15:51:55 -0700 (PDT) Subject: Re: [PATCH v2] iommu/arm-smmu: fix "hang" when games exit To: Rob Clark , Will Deacon Cc: Rob Clark , iommu@lists.linux-foundation.org, freedreno , Joerg Roedel , "moderated list:ARM SMMU DRIVERS" , open list References: <418d8426-f299-1269-2b2e-f86677cf22c2@arm.com> <20191007204906.19571-1-robdclark@gmail.com> <20191028222042.GB8532@willie-the-truck> From: Robin Murphy Message-ID: Date: Mon, 28 Oct 2019 22:51:53 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-10-28 10:38 pm, Rob Clark wrote: > On Mon, Oct 28, 2019 at 3:20 PM Will Deacon wrote: >> >> Hi Rob, >> >> On Mon, Oct 07, 2019 at 01:49:06PM -0700, Rob Clark wrote: >>> From: Rob Clark >>> >>> When games, browser, or anything using a lot of GPU buffers exits, there >>> can be many hundreds or thousands of buffers to unmap and free. If the >>> GPU is otherwise suspended, this can cause arm-smmu to resume/suspend >>> for each buffer, resulting 5-10 seconds worth of reprogramming the >>> context bank (arm_smmu_write_context_bank()/arm_smmu_write_s2cr()/etc). >>> To the user it would appear that the system just locked up. >>> >>> A simple solution is to use pm_runtime_put_autosuspend() instead, so we >>> don't immediately suspend the SMMU device. >> >> Please can you reword the subject to be a bit more useful? The commit >> message is great, but the subject is a bit like "fix bug in code" to me. > > yeah, not the best $subject, but I wasn't quite sure how to fit > something better in a reasonable # of chars.. maybe something like: > "iommu/arm-smmu: optimize unmap but avoiding toggling runpm state"? FWIW, I'd be inclined to frame it as something like "avoid pathological RPM behaviour for unmaps". Robin.